Integrate with CCK, Date, Sign Up to charge for events.

I understand people have used the E-commerce module to charge for events, but apparently this does not include registration and such, basically make the event node a product. I will try to do this, but I was wondering if you know of ways to integrate with CCK type 'event' usign the Date module, to actually register for the event upon payment confirmation.

I can help with user paths, UI, features, testing and such.

Thanks,