If you can't find 8/2, there might be some 12/4 3-phase around. Just pick any pair and put the ends together, and you have the same conductivity specs.
Well, just a short Google and looky here:
http://www.doityourself.com/icat/6and8gauge
http://business.search.ebay.com/romex_C ... catZ100016
http://electrical.hardwarestore.com/14- ... re-uf.aspx
I'm sure there are others.
Plus a little graph to make sure it meets your needs:
http://www.windsun.com/Hardware/Wire.htm
BTW: rewiring some shop equipment, or putting in a hot tub?
