Monkey, have you even built a guitar? I suggest you get REAL good at building them by hand first. Yeah, a CNC would cut out bodies and neck real quick, but it won't do the other important steps that go into building a guitar, such as:
Designing, wood selection, joining/gluing up, finishing, fretting, nut work, hardware installation, wiring, intonation/action setup, and of course SELLING them.
I suggest you get REAL good at what's listed above before you even THINK about a CNC machine, or you'll just have dozens of necks and bodies lying around your workshop.