At the end of D&D Encounters Season 1, two tables faced off. One made entirely of drow, the other entirely of non-drow. It was a lot of fun to play, and very dependent on how well the teamwork and synergy of the party was. With 12 players it took a bit of time but it was entertaining to do. The same guy who ran that also ran a PVP event at our last meetup, with prize support (make your best build and put it to the test in all out PVP action, last survivor wins. They seemed to have fun with that too, but I was a bit busy to watch it all.
So yeah, it can be done.