I finished wiring the C-64 Muse keyboard, and it does not work. Actually, 5 of the keys work. I delved more deeply into the C-64 schematics and discovered that I can't piggyback a second keyboard matrix on top of the first.
What I'm planning now is to use the PC board from a C-64 keyboard and wire the matrix lines directly to the PC board. I'll remove the keyswitch tops for those keys that map to piano keys. I believe that I can still use one of the matrix axes to reduce the wire count. This will increase the wire count from 12 to (8+4) to 28 (24+4), which is not as bad as 48 (24x2). Just thinking it would be nice have this done by the time of my Dallas trip so that perhaps I can visit Paul Slocum while I am there.