The Fisher Price record player has a simple tuned (for low values of tuned) metal comb in its "tonearm". Bumps in the grooves on the record flick the blades on the comb, producing notes in the same fashion as the bumps on the metal drum of a music box.
In a way it's a very primitive analog (literally analog) of a CD player, except FP used concentric grooves instead of a single spiral groove.
What's next for FP's record player? How about a precision tuned, laser cut note comb? I suspect the original is a crude stamping from garden variety spring steel. There's potential there for higher note density using narrower grooves and more notes on the comb, while retaining backward compatibility. A disc made to original specs would pluck several notes at once, providing some (insert adjective here) harmonics.
Or how about an electronic pickup of some sort, connected to a MIDI input?