not sure if you've checked the huge variety of home-builds on this forum, but I've managed to build the JOES2006 version which has been a really rewarding process and am achieving the accuracy you probably require. Check out my build thread in the link below.
Also check out Gully's (username Gully) version of the JOES. He has scaled it down a touch and achieved an excellent looking machine.
From my experience, for a home build, you'll spend at least $1500 by the time you're happy with the thing. Requires you to have access to a half decent workshop to manufacture the parts to the accuracy required.
Good luck and update this thread with your process.