Winunleaked.tk has updated its Windows 8 build number list with the latest version, which it claims is the final pre-beta version of Microsoft's next PC operating system.
The official build number is 8189.0.winmain.120120-1830. As previously reported, the next builds for Windows 8 will be labeled as Beta Escrow versions of the OS. The site claims Microsoft's own testers will then vote on which of the next Windows 8 builds will in fact be the final beta build with the decision being made on January 28. The beta build will then be shown at an internal Microsoft preview on January 30.
The road map now claims that the final beta build that will be released to the public will be labeled as winmain_win8b1.
Source
I know some of you don't trust Winunleaked.tk but but this source is as trusted as WinSuperSite IMO.