There's probably a way to do this in software? Like some cars simulating engine noises through the speakers...
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Though maybe instead of keying of an HDD LED, it should sit on the IDE/SCSI bus and generate sounds based on the actual access commands. That shouldn't be impossible, since the main market would be in retro-computing, and there are already devices that emulate those disks. Instead of figuring out what block to return, it would instead figure out of how long of a seek would have been needed and play the right sound.
If someone produces something that can simulate the sound of a 20MB Miniscribe drive, I'd buy it in a heartbeat: