gauging interest: Montana plates
I recently helped a friend who had trouble smogging his car register it in Montana. Although better known for the guys who get out of paying state taxes for their supercars, we found it also works well for registering cars that might be tough to get plates for in some states. Since my friend's car sees a few hundred miles on a good year, I don't feel so bad about the environmental implications.
Anyway, I learned how to do it. And I could do it for less than half of what the local law firm charges. There's really no reason to use a Montana law firm, since the risk, of course, is in the home state. For cars 11 years or older, Montana offers a permanent plate/registration, so it's a one-time deal.