Windows 8 is supposed to make it’s debut in first quarter 2012, if a roadmap from Dell is to be believed. I don’t see it happening, unless we see a beta very soon.
While details of the tablet are not known, what is known is that it is expected to land in Q1 of 2012. If the tablet is supposed to launch then, it is easy to assume that Windows 8 will have been released for public consumption at that point. But this date does not tie very closely to other dates that had been leaked, so that Q1 2012 launch window for Windows 8 may be a bit premature.