I have been thinking about the same problem. lets pass on information about
it.

a few of my thoughts.

1) just go by a dune buggy gas tank and mount it in your roof rack. put a
small fuel pump on it and a hose and when you need gas just stick the hose in
your filler cap (or anything else) the tanks are real safe, in Arizona dune
buggys had them in the heat all the time without a problem. my only fear
would be parking garges and low branches.

2) I once saw a gas tank in the shape of a tire. held about 20 gals. If I
could find one I would place it in the spare tire mount then find a way to
mount my tire somewhere else (on a rack on the back). I would then hard wire
a electric fuel pump to pump gas into my tank with a flip of the switch.

jjust an idea

todd T
84 westy