7 7970 on MSI Z77A-GD65 ---

[BryceMiner]

Won't the OP's setup be obsolete when the ACIS boxes zerg the network between now and end of October?  Seems like a lot of effort and money to end up with a loss...

...but I'm just a Noob.  

Yes, bitcoin GPU mining is long dead. But GPU's are still used (and profitable) for scrypt mining like Litecoin, Feathercoin and other altcoins. Also depends greatly on your local electricity costs.

As a followup to the ops question I was able to get 6 GPU's working on my gigabyte board with a "little" messing around in win7 x64. I'll be getting the exact same board as you next week so I will be shooting to hit 7 too. http://www.gobitgo.com/articles/1002/How-to-Mine-with-6-GPU/ has similar info that may be a helpful reference. In the link above the author is using windows 8 but the procedure is the same and works just as well in windows 7 x64.

Here's my version of how to get 7 cards working on win7x64:

1) Install 12.6 drivers. - shutdown
2) Unplug all risers, then plug in 1, boot to windows, insure the card shows up in device manager. After its detected and confirmed there, shutdown and plugin the next riser closest (left to right or right to left) and verify in device manager. If the card last plugged in does not show up it most likely means you will need to make a jumper to short the pcie pins. There is a thread on these forums outlining the procedure if needed.
3) Continue verifying all the cards and jumper the ones as needed. After you make it past card 5 you will see cards 6 and above show the yellow exclamation showing a problem. No worries on to the next step.
4) Download 13.1 drivers and double click to extract.
5) Do not install drivers after initial extraction. Click cancel to exit the installer.
6) Back to device manager and we need to update the driver on the devices with the yellow exclamation marks
7) Manually update the driver using the the 13.1 drivers which extracted to C:\amd\13.1... (you can follow the instructions in the link above if you need more specific details)
8 ) This installation/update does take a few minutes so be patient and don't try and close the device manager or updater.
9) On to the next one, same procedure if you have 7 cards.
10) DONE
10) Start Mining already!  

I am really curious to see if 7 gpu's are possible. I havent heard of anyone able to doit thus far on one MB...

[showtimex]

For sure its possible, maybe not natively with this board without the use of pci to pcie bridge but If you dig you will find other boards that support 7 and even one supports 8 cards natively (MSI Big Bang). The truth is out there

[BryceMiner]

Ive officially concluded that 7 or more cards on 1 gpu cannot be done. I hear a lot of talk but no proof.. I stand to be corrected.

[showtimex]

Yes, yes of course it can be done, you're getting confused with software driver limitation in windows vs your board only supporting 6 gpus. If you have gone through the process of jumping your slots like I mentioned previously and you don't have a card(s) showing up in windows it means your board is turning off that slot and its a limitation of that board, only other way to get more slots working on that board is to use the PCI to pcie bridge adapter which is around $20ish.

Only when you have 7 cards visible in windows can you then proceed to get them working by installing the two different drivers as described earlier. You said you got 6 cards working so I guess your're familiar with the install of the two separate drivers. But I'll explain again for the sake of others. We use two different driver versions to bypass (a registry limitation in the software) the 5 individual card limit in windows with driver 12.6 or earlier version, later versions only support up to 4 gpu's (for each driver). One could in theory run 4 cards off 13.1 and up to 4 cards off version 13.4 for example, but I have only used 12.6 and 13.1 together personally.

If one was comfortable with linux you could natively run 8 gpu's with one driver because it apparently doesn't have registry limitations like windows has. But it has nothing to do with the limitation of your hardware (motherboard) so you would still be limited to 6 working slots with that board.