Typically, CNC Machines take up a larger footprint than that of the raw material it is cutting. The size of such a machine may have prevented interested makers/hackers from buying or building one for themselves. If you are one of those people then you’d be interested in [Fly3DMon's] series of CNC Router projects called PhlatPrinter.
A typical CNC Router has a bed that the work piece is mounted to and that work piece stays stationary. The tool then moves in 3 axes, removing material, leaving behind a finished part. The PhlatPrinter works more like a large format plotter, where the work piece is moved back and forth via rollers while the tool only moves in 2 directions. What this allows is a CNC Machine that takes up very little floor space when not in use that can handle any length of material!
It appears that the first PhlatPrinter was intended to cut foam for RC Airplanes but a quick ‘net search shows a couple newer iterations, some of which cut wood and MDF. If you are interested in building one, the parts list, SKP and DXF files are available at the above link.