We track invitation lists in the Event Module by putting the committee members (volunteers) in as Registrants, and then their invitation list as their Guests. Then people go online and register. Because Online Express doesn't play well with invitation list based events, we are not able to fully use the functionality of OEx for this without having duplicate constituents. I would love to be able to download my registrations and gifts through an Event Form and have them update the people in my module who are on my invitation list.