Painting would probably take WAYYYYY more time and patience than I have. I did see a thread floating around here though about STAMPING bottle caps with the rubber stamps you get at craft stores, using a special ink that is permanent. That seems like something I'd be willing to do.
Wow, thanks guys. Bottlemark is way cheaper than I would've thought. I just didn't want the "BB" ones that come with my first Brewer's best kit. Kind of generic.