Now, this gave me an idea - perhaps someone here could help me out.

A computer keyboard that plays a unique note (or perhaps simple chord) for every keypress?

Might be a bit cacophonic, even for John Cage.

I once had a cat who had perfect pitch.

My late friend Sarah had majored in music, but had to retire her flute because her cat hated it so. Too bad she didn't know to switch to piano!