Speaking on the "chat" side of things, I think that has much merit re community building - my thoughts:
- use a dedicated room for the purpose; not the local "tavern" room (if you see what I mean)
- perhaps put up a scheduled event advert (the room owners can do this via the "events" tab)
- note that normally anyone talking would need to have legitimately gained the nominal (it really is small) minimum rep
- if there is a legitimate guest-speaker (i.e. the paper's author / experts etc), the system does support allowing them to talk, but this is now a moderator-only function - use sensibly please ;p And as you say, this may "suck them in"...
Actually, as part of general site advocacy I think I'd happily see things like this on a range of sites.