fuel cell ?

where can i get one of those cylinder shaped fuel cells looks like something from a big rig?

You could have one custom made.old school sandflat racers used the mooneyes tanks but they don't work well for everyday use.
Grip//NC\\OKC

tanks

is there any special reason the round tanks are not good for daily use?

Speedway mail order, thay carry alot of old hot rod style stuff.