Fine Line Automation might be an options for you. Fine Line Automation is basically shipped with everything you need and you need to bolt it together. Realistically, probably a 2-10 day project. It hasn't caught on like the Joe CNC, but it's very similar. If you do a search on CNCzone you will find a couple of people using them to make guitars. This is definitely an option under $4000.
Equipment: IS400, IS6000, VLS 6.60, LS100, HP4550, Ricoh GX e3300n, Hotronix STX20
Software: Adobe Suite & Gravostyle 5
Business: Trophy, Awards and Engraving