Chuck-
Are you thinking of the company called Vehicle Systems who make the Aqua-Hot and Hydro-hot Diesel-fired water heating and space heating(with hot water) systems? To me, this looks to be the real deal. The "works" of the system hangs off the vehicle frame, and heats the interior w/ small heat exchangers thru which hot water circulates. Website is
www.hydro-hot.com. Check it out!
PS- Danfoss has no "r" in it, FYI.