I think the only place a double sized would fit is on the pullout sofa bed. A single would fit in the entyway nicely according to a thread here a couple months ago. You may want to do a search for it.
I recently purchased an Eddie Bauer brand single air bed at Wallmart (or was it Target ?) anyway, a fraction of the cost of an Aerobed, with all the specifications. It didn't have a custom fitted matress pad, but I bought a nice padded cotton one for 17 bucks and it works great.. Even fits in the carrying bag too. I personally slept on it for three nights and it was the best sleep!