I liked several parts of each of these egg-mobiles from youtube: The hinged roof: The Wheel structure: I saw another one with chicken wire under the roosting poles, but can't find it at the moment. The south wall is going to be clear corrugated roofing to let in light and sun, the roof will be hinged, and it will have swing under wheels. The framing was done with some rough cut oak given to us by a friend that we ripped to 3 1/2 inches. It was so solid, we ended up using a finish nailer to put it together. I'll post a picture of the finished project soon!  Well, not finished yet, but it has a roof that opens with a hinge to air it out during the day in the summer!
Updated picture, but still have wheel structure to engineer: