There's an artist (David Milton) that specializes in painting old signs, buildings and including signage at the Neon Boneyard.

I've seen his work on display at the Laguna Beach (Calif.) Festival of the Arts for several years. Seems to sell well. The originals are in the $thousands. He also sells prints of some of them.

See his webpage for examples --
http://davidmiltonstudio.com/2/?p=374