Andrew hi, thanks for this!
I've had in the back of my mind for a while the idea to construct a homebrew CNC machine with modular head and boom sockets. While I have too many time constraints to actively pursue this personal project, it's something I'd like to at least implement the software for someday, being a dev! In my mind I'd like to build the positioning, angularity and momentum systems using hydraulics, variable torque mechanics & something driven by OpenCV+OpenCL fed by the Ruby extension to Google SketchUp. ^_^;
Looking at ROS and considering it coupled with the Parallella, it's a very convincing proposition in my mind
One of the best things I see right away is, using my little virtual project there as an example..If I were to build the hardware and software successfully to do, perhaps, a fancy wood lathe; I might one day come back and want to add a laser or camera onto the head.
If I had based my project on Parallella and ROS, I could scale, or if it had been a few years upgrade, my Parallella to enable processing and events for new the hardware.
Now talking about somewhere on the order of 40,000 voxels per cubic meter - you could use cheapo boards with an ARM. But in case people don't know, that's really not many voxels! To get very fine-grained detail you need precision mechanical hardware, computational hardware and computational software.