@Charles. Sounds great. I did a QnD register snippet using MIGX and some ajax embedded in the tpl. Works well enough but the backend is stand-alone as in you have to go into Migx to see the registrants. Good enough for the time being. Needs some front end jquery validation and maybe a simple captcha when I get around to it. See it live at http://skipngofarm.com/events.
I'll sure look hard at your solution when you get 'er done;) Thanks for all your hard work.