Frank,
I think what you are suggesting makes a lot of sense, it also sounds like a good rainy season project. I am up to my suspenders in pre-winter projects, but I will call you to discuss some thoughts and start to look for materials. My first thought would be to use some type of small gas engine, on skids that would fit in the back of the truck.
Does anyone know where to get specs on the torque and rpm output of small four strokes?
I will call you,
Rob