Yes. We're van campers and I blog about it and I've tried just about everything.
Our preferred setup is a full-size metal bedframe with a plywood base and a 10" full-size memory foam mattress. We use under-bed storage totes to hold our stuff.
I've experimented with inflatable beds for people who can't leave a bed set up in their van or SUV.
I found the Simmons Beauty Rest Skyrise mattress to be the most comfortable and durable. It comes with an inflator that uses 120V ac but will easily run off of a 140 watt inverter plugged into a cigarette lighter. It fully and firmly inflates in 2 minutes.
The only negative to an air mattress is that the air gets cold and siphons heat away from your body. We used several sleeping bags under the sheets to insulate us.
I am interested in exactly what you did
I made a styrofoam cooler with large cola bottles filled with water then froze. Used a small Dan and pcc pipe hose for direction. Not great cooling in a guest bedroom