The people behind the PocketNC heard you like CNC PCB mills, so they milled you a PCB mill out of PCB. They announced their surprising new open source hardware product, a pocket sized 3-axis ...
Figure 2-6: Simulation of a dual rotary mechanism fastened to the table of a standard 3-axis CNC milling machine. Tool length offsets work the same way here as with any conventional 3-axis machine.