Tim Heiser's AtomicSonic site has a huge gallery of hacked together homemade music boxes. Keyboards in Geiger counters, drums in water tanks and circuit benders in retro-televisions.
If you have a single hacking bone in your body I advise you to get over there quick-smart.
Heiser is a performance artist and musician but he also takes commissions for custom made gear. He doesn't do MIDI, but he has the important stuff covered:
Of course we do! What are you waiting for? Skedaddle.
Product page [AtomicSonic via Street Tech]
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