I've seen several but I can't remember where. Espar/Webasto/Planar website? I heard the guy in one of the diesel heater videos say that lots of European RV's are plumbed from the factory/converter for these so someone makes a ready to drop in flange I'm sure.
Good luck! Please post if you find it. I do know MGMetalworks did this on his gasoline Transit. You could try that thread.
Currently vanless. Weird.
Real name Eric
Finally found a pic of my first camper,
a 1986 Serro Scotty