This software and ethernet controllers also looks like an interesting alternative as the software is available on multiple platforms
http://www.bevelcutting.com/cnc-software.html


I like the idea of their self contained touchcreen one that runs the software on a cubieboard
https://www.youtube.com/watch?t=26&v=vIx-zgCEkKM

I wonder if anybody on here is using any of their products?