Windows 8 reached Escrow staging,
The last Pre-BETA build is the 8189.0.winmain.120120-1830 (end of coding).
Now, Microsoft working on the final Beta build of Windows 8, this step is called « Escrow » and started the 23rd January,
Some builds are already compiled from this Escrow step, 8191.0.winmain.120124-1748 and 8192.0.winmain.120125-1820,
Microsoft planned to sign off final Beta build this week then show this build during an internal preview.