http://www.automotivetouchup.com/spr...clearcoat.aspx
This stuff may be worth a shot. I have never personally used it, but have done A LOT of research in the past when I was going to paint my Jeep. And also, what you really need is proper curing to insure the paint is hard. Drying doesn't take long, but curing can take weeks. If you had a way to bake the frame, or get it really hot that would help the strength. I think the hardest part of the whole process would be getting ALL the paint off the frame.