Hacksaw
Thanks for the post ( The usual disclaimers apply )
I have that of which you speak of and It rocks!.
It works like this: Battery powered pump sends water through heat resistant tube. To a copper tube coil to more heat resistant tube and shower head thing. Below the copper tube coil sits a propane stove burner which heats the water up. tie this to a 20 lb tank and a river lots of showers. I think coleman come out with one with no heat, pump sends water to head type.

Lee