I didn't, but it was designed as a 4x12ft teardrop that you'd basically crawl through the door and onto the foot of the bed. Maybe a few shelves and lights.
If I'd taken it further, I'd have combined it with the shepherd's trailer chassis and that would open up the width and length to whatever you choose. With the rear entrance you're coming in on the sort side of the space, but a fold-down porch and awning are possible combining the retractable boat tail.
This is a superellipse, anywhere halfway between a square and a circle. Better than a box section for crosswind performance and shell strength.
For the material consider
Polymetal. I've only worked with samples, but these were sheared braked and rolled by handle (18" lever arm). More expensive than plywood but just as strong and it's
pre-finished. To me that's a big deal compared to (for example) fiberglass over foam. It comes in 4x12 and 5x10 sheets.
