I have no intrest in this company, but thought some may find these ideas and products helpfull. www.liftcoinc.com Tom Y
After looking at that site I started to think about other uses for the components they make.
How about using the "swing galley" hardware in the bedroom? Make a bottom cabinet (dresser) then have the mattress swing above it when not needed. That way you could swing the bed down onto the floor when not in use, you would not need the dresser at that point anyway. It would even work if you built the dresser over the wheel wells of some of the older GM buses.
If the dimensions are about what I think they would be, two of them would work out to be in the middle of the room for a queen size bed when down.
That would free the bedroom space up, and you could use it for a small office in the rear of the bus for working during the day, sleeping quarters at night.
Just a thought.
Jim