We'd love to do something like this - we're placing "beacons" around the site to provide uplinks for this kind of thing. We'd also like people to be able to see who they met up with or spent time with. But time's pretty tight, as the badges only arrive a week before the event, so submissions will be welcome.
Good plan - we'll be putting up some framework code on the TiLDA repo at https://github.com/emfcamp/TiLDA, so feel free to submit pull requests before the event.