Ok. Thanks everybody for all the discussion. If anyone has any other ideas, please post them.
What I'm getting from all this is that there is no obvious place to install a gas tank other than the extreme rear of the truck.
When I get my truck, I'm going to revisit this and look at the frame myself and see if I can get creative. If I think of another option, I'll post it here. Otherwise, I'll put the tank in the rear and look for ways to strengthen the frame back there. That will be good enough. I know I'll feel better with the tank out of the cab.
Thanks again, everybody!
