I don't know a thing about them except seeing this duo use one to great effect but is it was midied to an arranger , something like BK7m , couldn't the keyboard be split so the right hand is doing leads and fills the the left hand could alternate between chording and articulations .???
Backing tracks controlled by a foot switch are another option.
Doesn't seem like the Keytar was ever taken too seriously, kinda like Arrangers.