So I decided to put my money where my mouth went* and bought an Xplained board for an Xmega A3U. The current plan is to string up a quadrature encoder, and use the two DAC channels to give me analog position and velocity signals I can see on my 'scope.
If anyone has done this before and doesn't mind me picking their brains, let me know... ;-)
Eventually, the idea is to set up a PID loop and feed the error signal into a linear power amplifier (no PWM, thank you) and make a motor (with optical encoder on its butt) behave itself.
PS - I've done this many times before with PLDs and CPLDs, on a dozen custom boards, but this is my first effort with an Xmega. S.