Awesome job on the trailer.
I've been hunting around for a while, and have been planning to build my own trailer but I'm somewhat conflicted about size. I'm planning to make a steel order on Friday and start on a basic frame a week later.
I like that you made the main box separate from the frame. For my trailer, I want to be able to use it as a utility trailer from time to time. I also thought standard trailer springs looked awful short and have been looking for alternatives. I'm considering buying a pair of hubs from a Grand Cherokee front, fabricating custom knuckles and making MC2 asummetrical links, but the trailer will ride on leaf springs initially. What is your spring center width? What are your external dimensions of the main and side boxes? I'm looking to construct a lid for the main box, but my design looks a little tall. I drew it up as 56" wide x 84" long x 36" tall with a 6" high lid. It's probably considerably larger than yours, but I'm intending the flatbed portion to be able to carry 8' lumber when needed.