Next time you are passing through Illinois, swing by Peoria and I'll loan you my two channel Tektronix. It's an analog model from... late 80's?? Not really sure. The bandwidth is 100MHz, so it is more than fast enough for the voltages from a hub dynamo.

If anyone is curious about what the waveforms look like, let me know and I can try to grab some photos or short videos.

Steve in Peoria
(...but thinking about picking up one of those intriguing cheap Rigol scopes)