[skyking]

Here is the first sketch of the trailer.
It has a roof that pops up 18"~24". I have not finalized anything, so the heights are still 'soft'.
Interior height is 70" collapsed, 88"~94" raised.
It has adaptive suspension that can raise it up 6" for driveways, railroad crossings, etc. This allows for a low 6~8" ground clearance at highway speeds.
I have pages of floor plan in my head, but that does not affect aerodynamics.
It will be faired very closely to the tow vehicle with movable fairings. Tow vehicle height is 72", trailer is 90" as shown.
Trailer starts at 80" wide to match tow vehicle wake. That may be changed with advice from aerohead and others. It tapers to 96" but I would happily start out wider if I can be convinced the drag penalty could be minimized.
Radii will not be true radii, but constructed with ~1" slices of plywood to approximate one.
I've been conflicted about building it 102" wide. Wider = more drag, and several states have areas with 96" maximium widths. 102" would give me a little more room to plan with.