I am a little suspicious of that solution. Estlcam has provision for an arduino controller, but I don't know where you would get one, how it is programmed and what functionality it offers. Being Arduino, it ought to be open source.

Having said that I took a look on t'Interweb and found this http://blog.protoneer.co.nz/arduino-cnc-controller/ - interesting !

Cheers,

Rob