Set up Pool Play system!!
I know that I'd be very interested in another option of a challonge: Pool play. This setup usually involves a certain number of teams in each pool who play each other within the same pool in order to find a ranking for a subsequent single, double, or modified double elimination tournament. This is the process to Volleyball tournaments across the U.S. and would add LOTS of users to the challonge family.
Merging this with the multistage feature request – (which is currently being developed):
http://challonge.uservoice.com/forums/44455-feature-requests/suggestions/543069-multi-stage-tournaments-preliminary-round-robins-?ref=title