I just picked up the Behringer B-Control Rotary, and it's actually pretty decent for what i'm using it for.
I've got my sidstation and have been wanting an easier and more intutitive way to dig inside of it. I've just been messing with it for a few minutes, and having a cheap bank of 32 extra knobs and 16 extra buttons sure does help. I've gotta make a good preset for my machinedrum and Akai sampler now...
Also in PT 6.7 you can assign anything basically to Midi... so i'm thinking it will be a nice toy then as well, when i get a Digi002R or HD instead of my Digi 001 here at home...
Neve couldn't have made me a better 150 dollar bank of knobs