I remember this very old organ from Viscount before chord recognition where you would just hit a combination of keys to get your chord. the base note would pick the key.
So if you hit:
C and E it will pick C Maj
C and Eb it would pick C min
C and D it would pick C 7
and so on.
However, ideally I’d like something that I can use on the octopus without an external keyboard.
More than that I would like to take distance from the arranger concept (chords) and to think in scales and scales modes, ie. know your dorian from your aeolian, I think it’s easier to get something useful out of improvising in this way.
Anyway I’ll have to think a bit more about it…