Neat Idea but I've heard rabbits can get bad diseases and Parasites from being kept on the ground. Rabbits can be the King of their bunny kingdom with this easy to make rabbit tower, they can shelter underneath too.
Large Indoor Rabbit Hutch, DIY Rabbit Cage Ideas & Accessories
DIY: Guinea pig cage that was a TV unit in a former life. A ramp connects the 2 levels and there is a sheltered sleeping area plus lots of storage. The guinea pigs' favourite spot to sit is right in the middle of the ramp.