Back in the 70's I sold a 32 ft 5er to a gentleman with a Cadillac Coupe Deville 2 door hardtop. He pulled the 5er with the Coupe Deville with aN Ace hitch.
The hitch had two dolly wheels, had a double reciever, on on each frame rail of the Coupe, an had the fifth wheel on a frame that laid over the trunk lid.
We had the hitch painted white to match the Coupe and the 5er, which was a Country Aire.
The biggest handicap was high centering on the tow vehicle on a very steep incline.
Back then, trucks weren't very popular in New Jersey and some folks just want a 5er.