If you have the room to store it, an Aero Bed (as seen on TV) is a good alternative to the typical air mattress designed for camping. When filled, it is a true "queen" mattress that can use fitted sheets if you desire. It is considerably more comfortable than any camping air mattress I have ever used, and nearly as comfortable as my bed at home. It does take up more room than a "camping" mattress when packed, but comes with its own compressor. I borrowed one a few years ago to use in the camper shell of my truck and liked it so much that I bought it. (Actually, it probably needs less space to pack than a 2-person cot.)
The compressor runs on 110v, but I usually power mine with an el cheapo 300 watt inverter plugged into the cigarette lighter. (Admittedly I have to run the engine to provide enough juice to power the compressor without getting a "fault" light on the inverter, but I doubt I would need to if I had a "real" inverter, and I only need to run the engine when filling the mattress from empty. Don't need to when just topping off.)
Just a thought.