I really like the Compact 3 design. In fact, I spent a lot of time trying to make it work (for me). The problem I ran into was that by the time I got the ground clearance I wanted, and made the overall height of the trailer fit in my garage, the fixed ceiling height made headroom over the bed a bit too low. If ground clearance for rough roads isn't a concern for you, then you should have no problem making it fit in a standard garage.
I was also fully insulating everything, poptop included. That cost me inches in every direction.
I look forward to seeing what you come up with...