Tech website, SemiAccurate, is reporting that Microsoft's Next Xbox may suffer a delay, before it's even been officially announced.
According to the site, it has been hearing about problems regarding the 'Oban' chip within the system. Apparently yields on the chip, which is being developed at several manufacturers in the East, are said to be something between "painfully low and worse than that. In fact, one source even goes on to say that, "yields are not even up to horrid yet."
With this in mind, it seems like the December date in which Microsoft was hoping to start volume production, may not happen. SemiAccurate does add that breakthroughs can happen at literally any time, so there is still lots of hope.
The website does suggest that Microsoft was hoping to launch the system around September 2013, however if these issues aren't resolved, then it seems like we won't be seeing the console till late 2013 /early 2014.