I found this article today about two atheists that made documentary film about the Christian Music scene. They spent several years attending Cornerstone Music Festival (a festival that I have been to 3 times).
The result of their work is a film that some reviewers are hailing as the most objective perspective film they have ever seen. Impressive from two non-Christian filmmakers.
I liked what I read so much that I bought the film. Talk to me if you would like to borrow it or you need more information.