2011 Windows 8 to be Relased

The Windows 8 release date has been shrouded in a cloud of rumors. Most experts expect a late 2011 early 2012 release of the operating system. A recently leaked Windows 8 product cycle chart provides the answers needed to determine the release date of the next Windows OS by Microsoft.
You can take a look at the image here. The chart lists the planning, development and readiness product cycle of Windows 8 and related Microsoft products such as Internet Explorer 8, Windows Live Wave 4, Windows Live Wave 5 and Windows 7. It also lists major events.
Some events and products have already been held / released and it is possible to pinpoint the release date of Windows 8 by making the remaining calculations.
Here is what we know. Forum I and Forum II have been major events, the former held in December 2009, the latter in April 2010. The listing lists four additional event, Forum III to Forum VI. The next two events fall into the development phase of Windows 8, the remaining two into the readiness phase.
Internet Explorer 9 and Windows Live Wave 4 have either been announced with final dates (at least for the beta) or released already.
Forum II was held 4-5 months after Forum I. If we take this approach we can calculate the approximate month of the other four forums. This would mean between 16 to 20 months from April 2010 on which coincides perfectly with the projected late 2011 release date.
The Windows 8 beta should be released around June 2011 and the final release might even hit the stores at the same time that Windows 7 was released, which was October.
The Internet Explorer 9 product cycle confirms the findings. Microsoft has announced a beta release of Internet Explorer 9 for August 2010. This would be the same time that Forum III will be held, which is exactly four months after Forum II.
The chart may be a bit off since Windows Live Wave 4 was released in June. It could be that Microsoft has projected the Forum III conference for June / July instead.
Could also be that the chart is not 100% accurate and it can happen that development cycles need to be shifted, especially if major issues are encountered during development.
Still, we are pretty sure that Microsoft will release the beta of Windows 8 in or around June 2011 and the final release of the operating system in or around October 2011.
What’s your take on the chart? We are very interested in users who can provide us with additional information including Forum III to Forum VI dates.