Dayz BattleRoyale has reached Beta. Its themed on the movie of the same name.
40+ players start in a barn with nothing. There are backpacks on the ground, the horn sounds and you just run for backpack, grab what you can and get out of there. The map is fairly small, with mechanisms to pull players together as the game goes on. Looks like mental fun!!!
http://dayzbattleroyale.com/