Win 7 Beta was NOT released on 9 Jan 2011. You mean 9 Jan 2009. As far as the leak, you mean 27 Dec 2008, but I was downloading it on Christmas Day (25 Dec) 2008. So, I know it hit the scene at least a couple of days before 27 Dec. As far as Windows 8 Consumer Preview (CP), I will be VERY surprised if we don't see a leak in the next couple of weeks of what is believed or known to be the build being tagged as the CP. I just have a feeling we will see a leak at least a few days before the 29th, if not a week or two before that. Time will tell.
I don't think (from memory) that the build of Windows 7 given out at PDC 2008 was released early on MSDN or TechNet either, but they did handle the Beta and RC differently. The Windows 8 DP given out at BUILD is roughly the equivalent of the PDC 2008 build of Windows 7. Therefore, it remains to be seen if Microsoft handles Windows 8 CP in a similar way or hold off everyone until the big "show" on Feb 29th.