Like Theodore, the first thing that comes to mind is the Ketron midi modules, x3, x4, midij, etc.

You mentioned "less expensive". Don't know what you want to spend but a used Ketron module may be in your budget.

I have not used one myself, but have seen them used where the rhythms and bass/chords are controlled (or changed) by a midi accordion or midi keyboard.

If you are planning to control via the piano, your piano must be midi, right? and have a split so that a midi channel is controlling the bass/rhythm?

You can always get a set of midi foot pedals, and control the rhythm/bass with the tootsies.
That would be an aerobic workout for a Jazz/Blues/Jump-Jive player at my age!


[This message has been edited by MrEd (edited 02-15-2006).]