Over a year ago I was in Alaska and stumbled across another fellow Hummer owner (we were on a boat trip) and he was on land. On his roof rack he had installed two of the heavy duty plastic-flat boat fuel tanks that you buy for outboard boats. They each held about 15+ gallons and fit quite well inside the standard Hummer roof rack. He had the clip-on type fuel hose used in boats with the primer bulb in the hose. When he wanted to add fuel to his tank, he just pushed on the hose to the quick connect fitting, ran the hose to the fuel tank squeezed the primer bulb and fuel gravity flow took over. It's better and cheaper than a $2000 tank, not automatic and does require time standing along the road, but its not too expensive. I probably would not want to do this with gasoline, but diesel is much safer. You are only limited by space and weight buyt you could conceiveably carry quite a lot of fuel up there. Check boat catalogs like BOAT US. Just my 2cents.

bikerbill

...1996 4 dr Turbo Wagon..hi-gloss white (vanillia to me)..