There has been a need for this for awhile. Over the last 20 years, I have had alot of these pc based cnc controllers, on many different machines. The best ones to this date, I have had, were were centriod, linux based, and emc linux for sure.
Build a cnc controller the will cut parts, and do it well.
By far, the controller on HAAS mill is just down right awesome.
Some of the best applications I have ever ran, were open source, seems like the open source people really get programming.
Good luck with your venture
HAAS VF3-5 axis trunion
Mastercam X3