I've been reading threads on this forum non-stop for about two weeks now, and I've learned a lot from the discussions here. I'd like to first say thanks to everyone's sharing of experience and opinions.
Because weight is a major issue for me since I'm going to be pulling my tear with a motorcycle, I've been hard-pressed to find a building material that will let me build a 4x8 that is light enough to pull with the bike. I was planning on using 1/8" ply as a primary construction material until my mentor, a construction worker and woodworking craftsman, suggested that perhaps we could use balsa.
After researching balsa's properties, I think we can skip the thin ply and use 1/2" balsa for the wall/floor panels with 1"x2" balsa framing and 1" insulation foam. We're planning on going with a torsion box design using gorilla glue and liquid nails to laminate the layers together, and a shiplap to join each balsa board to the next. The two walls, the floor, and ceiling will weigh about 30lbs each, or a little less.
The cost of the balsa for the walls, floor, and ceiling will come to about $500 each, which is fine by me since the curb weight of the trailer when it is done should be about 250-275lbs. Well worth the cost for me and my application, and giving me an estimated total project cost of about $2500 to $3000 (possible discounts, deals, and sales not included). This means I can build the trailer I want for about 1/4 to 1/3 the cost of buying one pre-made, and I get to have the fun and enjoyment of learning a bunch of new skills along the way.
NOTE: I am always open to suggestions for build ideas and weight-saving materials. I am, however, trying to go for a classic woodie teardrop or as close as possible.