hey casper, im a huge fan of your work. 
so this graphic looks a little specific to a narrow margin of toys. ive rarely seen 3volt toys that's speaker is connected to the ground. usually one end is connected to the transistor and the other to the +supply. i think you should put up a tutorial on how to add an output to these toys too. your site is so well known that i think it would help out a lot of beginners. i dont even want to think about people plugging unshielded gear in to club pa's or expensive amps.:)