We used to have a motorhome with the door about halfway down the coach. I used to hate it because there was this big hole where the stairs were and I had to manually had to put a cover over that hole. It did not have an electric slide like the diesel pushers do. It seemed that most of the time when you are parked at a resort you spend most of the time in the living room, and that is where the hole for the steps were. If you were not careful and you had not covered the stairwell, you could easily over look it and fall breaking a leg or something. That gasoline coach also had a door in front on the drivers side which I also hated because it was hard getting in and out. The dumbest design I ever saw on a motorhome. Front door passenger side is the only way to go.
But if that is what you like then there are some older coaches that have that center door. I believe Alpine, and I think I saw some Safari Motor coaches that had that side door.