I saw Ean's video last night for creating a midi controller and having done my research I've discovered this: http://www.ultimarc.com/ipac1.html

I just want to know if anyone else has used it, and if it will be possible to wire in encoders.

From what I can tell buttons, knobs and sliders will be easy enough, but I want to add a couple of jog wheel type things and I think encoders are the way to go.