Yeah, heaving my 350 + pounds of dreamboat off the floor really sucked. It was easier to build up a bed frame than to lose 150 pounds so I did that. At least in a mid-top conversion van I can increase the height. 40 inch width, 27 inches underneath for storage, 2x4 framed, 3/4" CDX base, 4" of very high density foam on top (they used the same stuff to refloat the Concordia cruise ship).
I had tried a self inflating 3 inch camping pad but at the sight of me it deflated and ran off.