Blizzard just trademarked a very interesting "Mists of Pandaria". For the record, the international codes 009 and 041 only seems to appear on Blizzard's online games trademarks. This isn't a book or anything like that. It appears incredibly likely based on previous trademarks obtained by Blizzard that this is the next expansion.

Screenshot from http://my.mmosite.com/c594607f5bcd7c76cf7def70fe35ef7b/blog/ritem/054b706c22ae3e8d21c26ad40f7fd288.html