I'm a bit too busy with holiday action to post much now, but you gotta check out Japanese madman Kaseo and his circuit-bent orchestra of Pikachu toys. Not only did he rig one of these talking (now squawking, screeching & squeeling) toys with a theremin, he even sells them - if you can read Japanese.
Kaseo - Pikachu Orchestra (video)
Kaseo - circuit-bent Pikachu (mp3, different performance)
His site has tons of pictures of his custom-altered electronic toys, and mp3s, like this Hello Kitty telephone "tune." Noise, glorious noise!