I have seen tent campers with what looks like a high density foam mattress. It also inflates with air and is only about one inch in height. I don't know who makes it, but they swear by them.
Tony & Ruth........... FMCA#F416727
Newmar Dutch Star 4320, Spartan MM Chassis, Cat C9, Jeep Grand Cherokee,with Hemi, hooked up with a Blue Ox Aventa LX, and Brake Buddy.