If you are doing 10 gallon batches, I'd say you at least want a 12 gallon vessel for krausen and foam.
I've seen people use those.
You could also split your batch into two fermenters. This lets you expirment with different yeasts on the same batch, dry hopping one, kegging one and bottling the other for aging.... etc..
Lots of folks fermenting in Sanke Kegs.
I am moving in that direction, but was using a 15gal plastic conical. I like the conical but I cannot fit it in my freezer/fermentation chamber for temperature control.http://www.usplastic.com/catalog/item.aspx?itemid=25197&clickid=redirect