First off, just an amazing thread! To be quite honest, I wasn't expecting too much at the beginning of the thread. Lots of people have good ideas but few actually follow through. Especially with a project as ambitious as yours! As I watched your progress my whole perspective changed. Like others have expressed, I looked forward to each future post to see what was coming next. My expectations for the final product were pretty high and you exceeded them.
I had to smile when you wrote about not doing it for money, but rather the satisfaction of seeing others build and enjoy your trailers. That attitude is one that we don't hear expressed very often. I'm surprised how often I receive e-mails asking if it is ok for a builder to model their trailer after my Desert Dawg. When I was young my parents would tell me, "Imitation is the sincerest form of flattery". I didn't understand it back then, but I do now. I love the idea of someone liking my trailer enough to build one similar. I finally drew up a diagram with the basic dimensions that I could email people just to give them a starting point. I know that you aren't in it for the money, but I hope that your positive energy comes back to reward you bountifully.
With regard to the round VS square fender choice, I had to make the same decision when building my trailer. Ultimately I ended up choosing the flat top fenders primarily because I like the way they look. But after a number of years of regularly camping in the trailer I found that the decision was a great one, not for aesthetics but for a purely practical reason; storage at the campsite! The fenders become small but very handy tables on each side of the trailer. I set my small "packer" boxes on them rather than on the ground. At night my shoes get set on top of the fenders to keep bugs out of them and so they are handy for those night time trips to the restrooms.
Anyway, I've droned on enough. One last set of kudos on the trailer!
Joanne