Interesting find. An Android Pad would be interesting for a guy I know who wants something much bigger than a phone.
I stumbled across this description of the Drioid USB OTG hack http://www.tombom.co.uk/blog/?p=124. One picture looks the same, but there is also a close up of the plug.
This link is to someone who's getting USB OTG working on a Hero http://adq.livejournal.com/
I imagine google has pretty sophisticated searches for stuff they are developing. So the more interest in Android USB OTG, the more it's page rank rises, and the higher the priority on including the feature 
HTH
GB