I had a feeling it might be!

That is exactly the thing I was talking about in my post, thank you!

The Anatek Pocket range came out about 20 years ago. I've got the Pocket Filter. They need no batteries or PSU (powered by MIDI).

I believe the Pocket Channel will do you. Here's one for sale:

http://www.jimlaabsmusic.com/used-instr … _5930.html

You can also do it with this:

http://www.amazon.com/MIDI-Solutions-20 … B0002GH8IE

You hold the switch, hit any key the number of times equal to your channel and unpress. It can do some other junk too. I got it used for $40. The cool thing about the market for these is that they are hard to sell cause no one really buys them, so you can get a second hand one pretty cheap.

I found this funky little box for $20 at a used music store that translates incoming MIDI signals across channels. I don't remember what it's called, and it's down in the basement. If I find it I'll let you know what it's called.

MIDI Solutions makes these two products - either one is $150.
http://www.midisolutions.com/prodevp.htm
http://www.midisolutions.com/prodrte.htm

I guarantee you that it's possible to do this cheaper with an arduino (or any microcontroller).

As for mods to the keyboard itself, I did this, to put the touch strip in permanent pitch-bend mode:

http://kineticturtle.blogspot.com/2011/ … eytar.html

I have plans for more, including reversing the touch strip (so it goes the normal direction), and eventually making a sustain control. There may be a writeup about how I use the rockband keytar live soon by someone from Harmonix.

What's the best/cheapest way to use the keyboard to send MIDI through a different channel? Something like the mutable instruments midipal; or a way to hack the keyboard itself to switch channels with a button? I know it can be done with a laptop and a DAW; but I'm looking for something simpler.

Also; share any hax for it that you've seen online if it sparks discussion.