BF3Blog has word that some servers have popped up for the Battlefield 3 beta allowing 128-player games. The servers are apparently running the Operation Metro map, but rather than offering the 32-player rush mode like the official servers, they are running a hacked version of conquest mode, allowing 128 players rather then the intended 64. The bad news is that this is, rather unsurprisingly, a "considerably" laggy experience, and worse, they pass along Electronic Arts' warning that playing on hacked servers may compromise your EA account, and may earn you a ban, which can cause you to lose access to your other EA games.
http://www.bluesnews.com/s/126184/hacked-128-player-battlefield-3-beta-servers