Currently the driver has no support for reading data from google, as the provisioning API from google does not support it. I'm am looking at using the reporting API to achieve this functionality. The downside to the reporting API is that it only supports limited search functionality, and thus bandwidth would become an implication, as I would have to retrieve all data, about all users.
Currently no-one has requested this functionality so I've not given any attention to it.
Please let me know if you are interested/require this functionality and I'll see if I can fit it into my schedule.