You might consider one of the bunk models. It's not just how many people it can sleep, but also can they sit and move around comfortably. I have a Jayco 31FS and it has a queen bed, 2 bunks, dinette conversion, coach pullout, and overhead bunk. If you want a couch, which is much more comfortable than the dinette, it usually put you in a 30 footer or so. If you can get an E450 chassis with Ford's new 6 speed it really helps the gas mileage too. Winnie also makes a bunk model, Forest River also. Good luck with your search.