What's that Vox pedal all about?
It's all about horrible fake-tube aesthetics (other pedals in the range have a real tube in there but just as ugly) and great octave down, octave up AND two octave down fuzz
Yeah those voicechangers are a great simple bend or even pretty great unbent. Mine just has added pitch control and line in and outputs.
This is useful info for turning a toy's internal mic into a line in that works properly - http://www.epanorama.net/circuits/line_to_mic.html
(i think for the megaphone i just removed the electret mic element and replaced it with a 1/4" jack and it worked fine, some other such things i've tried didn't tho)