Greywolf, welcome to the forum. You have come to the right place, so it is futile to look any further. Some tears have been built on pop-up frames and I am sure you will be able to get some friendly advice from those builders. Now, if you are into cabinetmaking, a bit of a craftsman, have the tools and a place to build, you are almost there. (well, not quite).
With the trailer stripped to the bone, the design work now starts. You can get plenty of advice about the size, the shape and material you plan to use, just ask and you'll see. Pics are a good idea, we just love pics. We are interested in what part of the world you hail from and a few other things that you might complete in your profile. There are no strangers here, just a happy, helpful lot. Also, try to touch bases with other teardroppers in your area, one good look, is worth a bunch of pictures.

Good luck on your build.
Roly