I frequently use a midi accordion to control the Korg PA800. This video shows Jon Hammond using the midi accordion with a B3 and playing the bass parts with the accordion buttons.
http://video.aol.com/video-detail/midi-a...-1992/880750048

Something a little different. He stops by the Philly area now and again and does promos/concerts for the local Hammond Organ Center.
Ciao,
Jerry