You are looking for a cabin-style air tent. They have vertical walls which maximizes the usable space. I bought an inflatable tent house design specifically for this reason. We put a double-height air mattress, a rug, and a couple of chairs inside. It feels huge, literally like a portable hotel room. The Coody models sold by RBM are great for this because the beige canvas looks really classy and glampy, not like a cheap plastic tent.