Yeah, i'm just a little unconfortable with the concept of using anything that burns something for heat inside the truck.
I've priced out portable generators such as coleman powermate 3750 (pumps out 3000watts) $360 at pepboys. This idea would work; The company wouldn't have any problems with me bolting one to the catwalk. And then i would just use a small ceramic heater. Fetching gas everyday is not what i consider a big deal. I forget how large the tank is, but coleman says it will run for 10 hrs at 1/2 load.
The idea i find most interesting is to use deep cell batteries and an inverter.
http://www.idlefree.net/