I have wanted to do that for years. I even looked for several years for a late model Bigfoot 5th wheel to buy for just that purpose, but never found one. They stopped making them about 1994 or so. The Bigfoot 5th was about 20' OA, so it would have been about a 13.5' camper. It had the best arrangement I've ever seen in an RV. I had a 1984 version but had sold it by the time I got the idea. Escape currently makes a small 5th that might work, its very similar to the old Bigfoot.