Hey i don't know if your still looking I can easily build you a trailer, but I would refer you to some of my buddies who build them for a living to avoid the dmv headaches. Depending on your budget for it (is it long term or disposable) you could always buy a throw away harbor freight trailer for $200ish and get a new one every few years or for around $1000-1500 get a custom galvanized trailer from my buddy or I could build you one for about the same as him
Lmk if I can help u in any way