Brian very nice build. I really need to find time to get working on mine. I got the Bantam TC-3 that Dabrode had on Cave76, as I am sure you know it needs some work.
Have you looked into the Lock 'N Roll hitch, since you want to have this as an offroad trailer?
http://www.locknroll.com/
(i posted this on JF too, before i remembered I had a log in here)
-Paul