Although not exactly what you are asking for, I did build my own CNC system and I do use it successfully for isolation routing of PCBs.
True it is not as fine-lined as a photo process, it is a lot louder and makes some dust, but there are no nasty chemicals & such. Like life, it's all about trade-offs.
Anyhow, you might pick up a trick or two from my blog. Cheers and good milling.
http://woodworkerbcncrouterproject.blogspot.com/