Finding a motor and gearbox assemby is easy enough, you can just use a large servo with no guts in it.

I'll give this a go, and hopefully a few others might give it a go.

I was kinda inspired by other useless but funny things I've seen, for example Ray Tates dancing table lamp that was demonstrated at Burgess Hill, very entertaining toy I told him he should lend it to Pixar because it is very similar in actions to their mascot.