There are times when I have access to free or cheap electric.
The thing is, I don't want to cart a tower unit around with me. FPGA makes no sense because that's cheaper on electric anyway.
What's the smallest a mining rig can be? It doesn't need to be efficient on power, quiet or light. But small is good.
I have to carry round a laptop anyway. How's about this:http://hackaday.com/2011/10/19/beefing-up-your-laptops-gaming-chops-with-an-external-gpu/
How fast a GPU can it take I wonder? My laptop is on the compatible list:http://forum.notebookreview.com/gaming-software-graphics-cards/418851-diy-egpu-experiences.html
Lugging round the PSU would be a pain too.
Found this on ebay but when I look in my PCI express slot it appears it wouldn't fit (confused):http://www.ebay.co.uk/itm/PE4H-v2-4a-60cm-Flat-mini-HDMI-EC2C-SPB087-ExpressCard-PCI-E-Adapter-/180808629729?pt=LH_DefaultDomain_0&hash=item2a1908bde1#ht_3307wt_905
"ExpressCard (54, 34)" in my laptop.
Hope this has inspired
Sorry if this is a silly thing to say but it should be pointed out that you don't need a client or blockchain for mining with a pool. Took me a while to figure this out as most guides mention downloading a bitcoin client