Unofficial explanation of the Nikon D800 autofocus issues
Falk Lumo was at the Photokina 2012 trade show and talked to a couple of Nikon officials (customer support manager and technician) and has published - in his own words - an explanation of the Nikon D800 autofocus issues, including the cause and what Nikon is planning to do about it. Please note the aforelinked post is Lumo's write-up of the meeting. It is not an official Nikon statement! You can also read the above post in German.
Having said that, it is great that Nikon customer support has been so forthcoming to discuss this situation with photographers and not block the publication of it!