GPS Tracking for Stolen Bikes

BillB we had a police freebie bike tagging day at work, this is just a simple scannable chip about the size of a pill, but the mounting system could be used for this, it was a plastic thing a bit like a mini badminton shuttlecock that is pushed down the seat tube, now if you could power it by a simple rotating magnet on your BB (I'm thinking old style loose ball BB here, bond a magnet or two to the axle) and coil on the actual transmitter.

That's the thing... powering it after the theft.

I like the idea of the bottom bracket itself being part of a dynamo, so that pedalling is generating the power without friction.

I'd imagine for this to suit our needs the electronics would have to be hot glued into a tubular shape, and the device remotely configurable by TXT. The bike frame would have to be the aerial, otherwise the frame could impede the signal. And the BB the heart of a dynamo, so that it never needs batteries replaced.