I don't know what the situation is in the U.S. (assuming that is where you are from). At least where I live, and AFAIK, there is no central repository for such codes that is correct, regularly updated and free. Of course it's possible to gain access to such databases, but that tends to cost quite a bit, again... at least where I live.
My main point is that I think you need to turn up not just with an idea (those are a dime a dozen), but also with some concrete points about how the solution would work, most importantly, where this data would come from and how it's guaranteed to remain current. If you can do that, I'm sure you'd have a lot easier time piquing a developers interest.