Today a user called Canouna has just tweeted, stating that the latest build compiled is Build 7949.
This build is also a part of Milestone 2 Escrow category and the complete build string is 6.2.7949.0.winmain_win8m2_escrow.110222-1545 which states that the build was compiled on Feb 22.
This from Windows8beta.
Hat tip.