Always cool to see ‘retro’ tech brought back, especially with major overhauls. Kinda wish Apple still did dedicated ‘dumb’ MP3 players, if I’m being honest.
Bet you could manage with a microcontroller and some parts. Use a bare chip, solder it all fancy (might take a few tries, use something cheap, order in bulk, attach the big expensive drive last), print the case, etc. Bet there's even a guide out there somewhere.