Yeah u can it works great. I have been using one for 3 years. I cut a hole in the top of it with a tourch and used a factory pump and sending unit out of a factory tank. Just wash it out with hot water 3 or 4 times and it should be ok to cut.
It would be kinda small... Doesn't seem worth the effort IMO. If you have an aluminum fork tank, you could easily sell it for $75, which is most of what you need for a fuel cell.