There are a lot of good shops. My company uses Inland Body and Paint in Fontana. We've been happy with everything that they've done. http://www.inlandbodyandpaintcenter.com/

I drive by Gongora's just about every other day. They always have customs/hotrods/projects in their shop. I see them at the local car shows, too. http://www.gongorasbodyandpaint.com/

So Cal is a big place. Did you want to stay close to home?