One of the developments that I have my eyes on is the TI BeagleBone platform being used as a CNC controller for 3D printing. It's PRU coprocessors seem ideal for offloading the syrup and direction management while the main CPU does higher order work.
Well, it appears that Charles Steinkuehler has gotten his BeagleBone running LinuxCNC to control his MendelMax, and has the video to prove it! This is an important first step to get beyond the performance limits of the current crop of Arduino/AVR-based print controllers.
... and he's even got his scope trace showing how smoothly it can accelerate to 40kHz stepper timing.