Android Central has posted an alleged leaked screenshot showing that Dell would be releasing a Windows 8 tablet in first quarter of 2012 codenamed as Peju. According to the details this tablet is scheduled to be released in CES 2012 and going by the values on the left, the size of this tablet would be around 10 inches.
Though according to the news available Windows 8 is scheduled to be RTMed in late 2012, so is Microsoft planning to release Windows 8 for tablets much more before the timeframe. As Microsoft has already shown Windows 8 running on Soc chips in CES 2011 so their might be slight possibility that Windows 8 for tablets is released much before the version for the desktops.
Another leaked roadmap by Android Central shows that Dell is planning to release the next version of Windows Phone 7 in July 2011 with codenamed as Wrigley