Relocating Gas tank on 70 chevy truck

[70Chevy4x4Nut]

Does anyone know if someone has tried to use a saddle gas tank from a 73-86 chevy or ford pickup. It looks like a person could also cut out a filler door from a ford or chevy truck or car and weld/blend it in to the side of the bed and give it a flush look. The bed would have to be notched a bit to make room for the filler tube, but didn't they do that on some trucks. I hate to get rid of my spare tire and I also don't like the idea of filling from inside the bed. I really don't like the aluminum filler doors that fit on the crease. I like the flush look. I'm sure someone has looked into it so maybe I just don't know the details. Any help would be appreciated.