This camper is built over a 1956 Cadillac Sedan de Ville. This is the first time that I've heard of such a vehicle, but apparently there were many of them made in years past. They're called, appropriately, "Caddy Shacks". eBay seller sportscarlacalifornia is offering this one for sale.
Link via Jalopnik
seen the dozen and more online .... and each one more fugly then the next
bunch of bleeping " " smokers
Good luck with that sale.