We just sold our queen spare bed and purchased one of those plug in air beds. It automatically inflates and deflates. It's quite high not like the old fashion air beds. DH jumped on and did a pretend thrust x10 and he thought it was excellent bahaaa. Have had 2 lots of guests stay and both were so impressed they went and purchased one too!
It works for us as we put it in the third bedroom but means when people aren't staying we can use it as a play room still.