I've been looking for an old link to a good DIY rim repair, finally found it in my bookmarks. I did a search and didn't see this posted anywhere here. This guy did a really good job, might be worthy of a sticky if someone wants to take the time to copy and paste the whole thing into a post here.
http://www.audiworld.com/tech/ext43.shtml
It's a porsche wheel, but the same technique works for anything. You would just need to know the color paint you need.