If this is done the night of the rave, as opposed to the J-Pop dance, I'm totally in with helping you run it my friend. =)
And I LOVE the idea of two rounds where people switch out so other's can join in on the fun. It'd be messy (like anything new at cons) the first time it's done, but this would be a great help to the solution of popular panels in small rooms, once the kinks were perfected on how to go about doing it.
I believe you told me Sakuracon is doing something similar of this nature, where they have an event people who RSVP'd on the forums gets first dibs at going. Another good idea, but I can see much wrong with it as well, that'll need to be worked out in order to prefect it.