Chrysler underneath in the mechanical dept. Travco made, I believe in Brown City, MI. The father of a friend had one back in the 1960s. I believe there's a website dedicated to them.
Travco, model 210 (21ft)
My parents own a 1975 model 270 (27ft).
Dodge truck chassis, 440 engine. Fiberglass shell over steel framing.
There are websites, Yahoo groups, Facebook groups and blogs dedicated to them.