Musicians, authors, filmmakers, artists, whatever. Lots of creative people are able to leverage a dedicated fan base into a livable, if not insanely lucrative, salary.
The key is to provide something scarce. Since books, music, etc. are digital, they no longer are scare, but you can offer things like a day in the studio with the band, or for an author it could be advanced drafts, a $1000 dollar option to get your name as a character in a new book, signed special editions, you name it.
It may not get you to the top of the NYT Bestseller List, but if done with an eye toward your core fans, you can absolutely make a living on your art.
There is a whole list of them at: http://www.techdirt.com/blog/casestudies/