I know a few people who had their satellite radio antennas painted by a company called Colormatchantenna . You can either buy antennas or PnP systems from them that come already painted or you can send in your antenna to get painted. It costs ~45 for the painting service - it is a bit of a premium good - but they look beautiful and they work.
Yes the antennas can be painted for metallic colors. In reality the paint doesn't contain any metallic elements, it is sort of a synthetic additive. Almost all manufacturers have been using that kind of paint. But some body shops may use a different kind of paint with real metallic.
I found this post while searching for our company, and please to know digitalelegance has a presence here.