In theory, yes.  Actually, If I ever get a game up and running, I'll accept altcoins because the goods are virtual anyway.  For a real retailer, however, there is definite risk.  Grocery stores operate on a slim 4% margin.  Meaning that if they accepted BTC and converted it to USD and it dropped in the interim or was fake, they would lose money.

Additionally, adding a 10 minute wait while the transaction was verified would be a problem for most retailers.  Even a company charging a credit card like processing fee might have issues.  Fun.

P.S. I generally prefer tons and tons of transaction records.

Let me know if you can think of a way to have a solid transaction record to prove repayment in BTC as I would prefer to repay with mining efforts.

It works out this way for me:  If I repay in BTC:  100% gain, even if I pay more in BTC.  I get a video card for the cost of electricity I have to pay for anyway.

Repay in cash: same as if I bought the video card.

Straight up buying the card, no gain/loss.

Trying to earn BTC for myself: even worse than just buying the card.  It's actually more practical to buy it and fold.  Though I can work it better by bartering, I think.

Was thinking of getting a loan in bitcoins, to get a mining GPU.
  (Will a pci 1x slot work for a Radeon 6770 or thereabouts?)

The problem is... it would have to be a loan in cash with an option to mine BTC in return and I would need weekly confirmations of my effort.

I was reading the PayPal thread. Bitcoins have no printable transaction records. Where's a bit credit union when you bit need one. (I'd say Bit car.... but I think that's taking it too far and Batman might sue).

I've also figured out the 'end of bitcons' / ultimate death of the currency.  (Should happen once it's no longer profitable to mine.).  Not sharing / don't care if I'm right.  Bitcoins are still useful in the short term and may be fun!

Anyway, my goal is not to get a loan in BTC.  My goal is to get either a video card valued in $$$ with the option to pay back in BTC or a dollar amount sufficient to buy a card in BTC converted into $$.  The card would not be mine until paid for and I would be known to the card owner and could be taken to small claims court.

I can just pay cash for the card.  And would likely do so if asked to send it back. (The shipping is 8. My goal price for a mining GPU is 40-60, though of I have to

My problem is that if I mine BTC for myself.  Among other limiting factors (there are 3) I live in low income housing and I would have to report BTC sold in income which could get me kicked out.  Yeahhh... also, another factor means that I get no net gain from BTC mining and can't even recoup money spent on the vid card.  (Unless someone has a nice shell corporation.   I think the corp owns the card, borrows the cash for it, and pays me back... gahhhhhh, but then I still don't own the card. XD)

I'd like a good video card to keep me warm... I can get a space heater cheap... but it's more efficient to do something and derive warmth from the waste heat!  Like mining BTC.

I have to pay the electricity anyway.  I spend at least $30/mo extra warming myself.  Why not spend that to run a GPU?

Please no suggestions about me running asicminers, I'm generally pretty paranoid about getting robbed and I don't own anything worth anywhere near that much. (If I did, I'd sell new and buy used to mitigate risk).  Yes, I'd gladly give away the electricity needed to keep my room warm.  I'd use my X360 for a space heater but it's too much of a red ring risk to leave it running all night. (It's a 2008 falcon I've never had to repair).

Also, if anyone has an old card that it's not economical for them to mine with that they can't sell for some reason (not stolen, but maybe you had to replace the fan or something) let me know."

That's the behavior of the default/reference implementation, not all implementations follow this.  In theory higher fee transactions should be prioritized but I'm not sure which software, if any, has implemented such a system.  (Is it a net slowdown?)

Note to anyone reading this, I'm looking for my first bitcoin mining rig.  My room is too cold so a good Radeon 6770 for 40 or so and the opportunity to pay it back in BTC would be nice.

And if anyone knows of a simple to script/encapsulated BTC client let me know.   I may try implementing that myself.  Also, functionally, fee's are optional, there may not even be a fee on some blocks.

In my room it's a bit chilly.  I prefer about 75-85, usually closer to 85.

I was looking for a heater.  I heard you have them... I want one... free. 

Why would you send me one?

Simple.  I have a 500watt OCZ stealthxstream psu.  It sits idle.
I just got a core2quad dell optiplex 755.

Basically, If I earn bitcoins for myself it results in no net gain.  Heck, I'm paranoid enough that I don't even trust this computer to log into. a bitcoin account.  Online banking, heck no. (But if I understand it, I don't have to).

Let me know if there are any security concerns with an untrusted network.  But if I'm right, there aren't.   That's the point of bitcoin.   I'm going to be paying $27 in my electricity bill regardless and my tiny little optiplex 755 Mobo has 1 PCIe slot vacant.

Let me know if you're interested.  
I win: free video card, heated room. Net gain to me is probably around a hundred.  I'm assuming the $100 high end ATI's are in the sweet spot.
You win: don't have to run AC, bitcoins coming from secondary location, don't have to pay for Months of electricity.

Target break even point should be 3.33 months or sooner.  

The dell optiplex has an automatic on time, which can be set.  Windows 7 currently boots to lock screen, I'm looking into having it auto login.  Or installing Linux.  Combined with a file in startup (please tell me win7 still has startup.)   I'm not sure how long it will take to pay off in BTC but, obviously, I can only guarantee so many months.

Risks: 
 BTC could drop. 
 You may not get your value for the vid cards.  
Is malware on other PC's an issue, I'm very tempted to just sneak into Thr next room and type format:C
Summer may be too hot too let it run.
It can get humid here. (people from Texas complain some summers).

With the gold drop and the BTC value, I can see you easily pulling $200 even with a cap of 8 mos and march of next year. (Both would be limits, lowest applies).

I currently have a health condition which is trying to kill me, hence why it has to stay warm in my room.  Which is great except that my mom needs 70 degrees, I needed 85.  It was down to either bitcoin or folding and folding couldn't net me a free video card.

Oh, I should also mention, I have odd luck.  I've crashed a gas station pump, a change machine, and a computer all in one day, met a member of the famous band Parlament Funksdelic (I care, they were mentioned on Cosby) while shopping.  And I once tasked my luck with finding my ex g/f.  I walked 300 meters, I'd never met her outside of one building... except that one time.  I delivered her hot miso soup... I was that sure it would work, in spite of never having tried anything like that before.  It was on a small campus though, so odds were probably 600 in 10,000, or .6 percent.

Anyway, let me know if interested.  My Mobo only has one slot for a pcie card.  It's currently also in the mini btx optiplex case, which will be fun.   Btx uses a ducted fan for a CPU cooler.  I doubt the one on the Athlon is compatible. So I may have to buy one.

I once had someone on neopets (a game) lend me 100k or 1mil promising to pay him double in a week.  He went antsy, got all worried about it, and bugged me for the amount 3 days later.  I gave him 1.5 or 2 times... don't remember. I was using the sudden inflation around holidays to drastically create points.  Worked really damn well.  I think I ended up with 5 times what he lent me and I was going to give him triple instead of whatever I did.  Then again, it was just a game.  Oh, I would have had 10 times if he hadn't gutted me.  In the end, it worked out... I had fun.  I also netted hundreds of thousands of Neopoints my first week on the game without cheating!

Let me know if you're interested in working out the details, this is just a rough draft.   I personally have no faith in the value of BTC... yeah, over the last few years I would have been wrong... but I smell a bubble!  

So, how does that sound?   There is some risk..., my health comes first which means it won't be running or will be underclocked if the exterior temp goes too high.  There are two caps, but the two caps are tailored with a goal of 1.8 times profit for you (with a margin) and doing something useful with my heating bill.   The BTX to ATX transition could cause problems, etc.  

If we had done this last year, you'd have netted $100 profit... now?  Who knows.  But... last year I didn't need a heater.

Airflow is an issue, I want maximum cooling to airflow ratio... I'm less keen on the huge cards, but I do like ducts and am worried about dell Mobo's in general.

There's a Tom's hardware list that shows price/performance and paints a huge sweet spot at $100.  So that is the target of all my math as well.  The best bitcoin mining $100 radeon should be the preferred card.  If you're upgrading or drooling over months of free electricity and a potential 100% profit, let me know.  

I should be remedied of needing it 80+ (it was over 85 some nights, that's comfy)  degrees in my room in a few months... right around the time it starts to get colder.

I can't guarantee the value of BTC, but it would be cool to try.

Anyway, whether it's your old video card, or a new one, make me an offer.  Absolute cap is March of next year or 8 mos electricity, net.  The video card is 100% mine n paid for after 3.3 months. Profit goal is to break even in 3.3 mos, to net an 80% profit for you in BTC within 6 months, or it it's too hot, in 6months broken up over the next 11/12.   I'm looking for efficiency too, I'm still paying for my electricity and it would be nice to know that someone other than the horrible people at my local power company is benefitting even if it can't be me.  Bribes for more months in computer parts likely accepted.

Arrr, me bounty. Can't wait till I can post.