Or the CCA, Center for Contemporay Art. I think the CCA should have space for 40+ people, and most things listed above (except for session cards) http://www.cca.ge/
Those are some great ideas @Uli! Especially CCA! (Geoair has never replied to an email I sent them, so I am not sure how easy they are to reach). During the bi-weekly meeting we had yesterday we also came up with: ExpoGeorgia, The University of Georgia, Free University, Europe House and Caucasian house.