There's air mattresses and ComfortAire Bedz (sleep number style)! We use ComfortAire mattresses in our home and RV for years. Those padded things the RV manufacturers supply are not mattresses...more like torture. The sleep number systems are expensive, but so is a miserable night's sleep or trip to the Dr. for back issues.
In all seriousness, when we spend months on the road, it's nice to have a home feeling bed.