aerohead! Tag, you're it.
As you say you have a history with this sort of thing. I have a history of having trouble getting other people to build my ideas.
On that first model the edges are 4', 3' and 5' front to back. I started with the center section 3' long and the center at 18" to get the 135°/2 and 157.5°/2 angles to the center. The result is a short 'thorax' and a long 'abdomen'.
I'm currently making a 2nd model, same scale, same 10' length but on a 4x10 sheet. The edge lengths will be arbitrarily 4',4', and 4'. Also the wheels were pushed back so they could be tucked inside the max width; but I think teardrops are like that because of the weight of the kitchen in back. So the new model has the wheels in the (newly longer) center section with semi-enclosed wheelwells and half-fender/spats. And it will be skinned with corrugated material.
If someone was building one, I might go back to the 3D modeling and compare squircles at 45° to each other.
If I did build one myself, it probably would be based on my Westy utility trailer. I have a source for the (thoroughly thrashed) suspension parts via thesamba.com. It's a 4'x3'x1.5 box. Some redwood bows with temp bracing, with burlap shrunk to fit and sprayed with clear polyurethane would get me in the game.
