Just came across this 2014 overview article with photos, by linking to an image on Pinterest. It's a DIY teardrop that looks like a professional build.
DIY Micro Camping Trailer I Built for $2900
My favorite things:
The ingenious storage in the front of the TD, accessed through two little baggage doors; inside the TD, the storage area creates a head board and shelf.
The other thing I like is the vertical back with a large door that swings up to access the kitchen area; the door then doubles as a shelter/shade.
The builder mentioned how easy it was to build, because he's looked at a lot of trailers and knew how they went together. My guess is that he had extensive finish carpentry/construction experience prior to beginning this project.
Again, an aspirational article, NOT a how-to.