I bought some electric brakes from a wing guy who took them off his camper. I have yet to work them on a trailer but thought of a diy tear drop.
I did see an old vet running across america pulling one with a road king, it was home made and very small, made for one person. I spoke to the guy it was his 3rd build, each time they got lighter and smaller. No windows, just an rv vent ontop. His was made of 1/4" ply with a very thin layer of fiberglass and the back was painted florescent orange. He also said he wouldn't go over 50 mph and only took state roads.