I got the chance to play my with an Eventide H7600 in my rig a few days ago. It was a completely different world of effects processing. Controlling it with the MP-201 via MIDI is just too powerful and without too much hassle, I was able to create some incredible and unique sounds that I could never even have conceived of. Unfortunately, the H7600 costs about $4k.
But the Eventide Pitchfactor can be had for under $500 and has both MIDI and USB control options, both of which the MP-201 support. I have some gear to sell and I'm going to pick one of these up. They insane units, but I had always considered them too big, too much money, and too impractical. Experience has shown otherwise, however, so I'm making moves yet again.
Modulation wise, I might switch back to the nano small stone, Maxon Phase 90 clone, or pick up a Bassballs. The Source Audio is great but something about it isn't quite right and it's pretty big.