Just found
Measured data of many different dynamo models (not all models listed seem to contain data yet).
For quick orientation:
Reifenläufer = rim wheel type dynamo Speichendynamos = spoke dynamo Nabendynamos = hub dynamo
Also take a look at the summary (Zusammenfassung).
In the content you can also find a lot more information on dynamos (in German though).
I just took a quick look, so I can't give any comment to the quality/correctness of the information. But perhaps you can use the data for comparison.