not sure how everyone feels about plastic but heres a link I've found for some pretty inexpesive conical tanks http://www.tank-depot.com/product.aspx?id=854
the trick is the tanks don't come with a stand, which cost $123. You could always build one if you are handy.
I am planning to pick up 2 of these to turn into 15 gallon fermenters. I will definitely be building my own stand. I will add a dump valve and racking arm with ball valves. One point some people make is that they are hard to get air tight, but I am not too concerned about that for myself. A quick search for "inductor tank fermenter" will give lots of ideas. This place has free shipping for orders over $100 and tanks are good price. http://www.ruralking.com/catalogsearch/result/?q=inductor+tank+15+full+drain
