I think he is asking if a tank can be made in an oval shape rather than a cylinder. The answer is yes it can, but, this would need to be welded steel and have special approval from the DOT or CE (Canadian version of DOT). It would be extremely expensive. If you want a shorter, wider tank you might consider using twin 45's instead of a single 80. 45's are a standard size tank and are made in steel or aluminum. Check out http://www.luxfercylinders.com/americas/product_info/scuba/specifications.htfx.htm
for a complete list of aluminum tanks made by Luxfer for sizes in CU FT, length and diameter. It also lists weight, boyancy full and boyancy empty. DiversDiscount can probably special order any one of them, talk to their staff at 800-34-scuba for details.
Regardless of where you get your tanks from there are only 3 main tank manufacturers. Luxfer and Catalina for aluminum and Faber for steel. All the dive equipment manufacturers get their tanks from one of those three companies and put their valves, paint and emblems on them.