John..Ketron has been building what you need for years. A long time ago, they made a thing called an auto orchestra. Majors, minors 7ths and, I think, diminished chords were triggered off four button on the volume pedal. Contact AJ. You played the right note on conventional looking 13 note pedalboard. accessed rythems on a controller (or on a separate unit or arranger today), and "went at it". George Kaye or Dano could also fill you in. You would neerd the bass pedal devise and the arranger keyboard or module to do it.

good luck!


Russ