I took a squirrel (made from clay and scanned) and added it to the top of the la FabShop Mobile. It's easy to merge stl files using TinkerCad. I could have put Godzilla on the roof, or shrunk the squirrel down and let him drive.
The la FabShop Mobile is a fantastic design--it prints movable wheels without assembly or supports. My "squirrel on roof" version does require supports.