Sorry didn't post that one. I'll do it now. But basically you can put what ever you want inside the poly~, what I wanted to share was really the keyboard in itself - so everything in the "maxkeyboard" subpatcher is the important stuff. The poly~ was really only to show it works - it's a simple 1 osc synth.
I created something similar to this based on the [coll] object and a little bit of maths for the octaves instead of using [route] and [funnel]. Here's the patch and a helpfile if you want to take a look: