It looks like Harry has been chiming in a lot lately about 40k, which is a game he doesn't know much about (according to him). Today Harry has mentioned a couple codex releases that he expects to see for 2013. To be fair he was discussing his latest on the Autumn of flyers, however he mentioned this little bit.

via Harry
we get both Tau and Eldar next year and they both come with Flyers.

Also via Straightsilver
I would say Tau early 2013, and Eldar late 2013, but every time I hear about Tau I add about a year on now

Where this leaves the latest little bits about Chaos Daemons being early next year is still a mystery. However I put a lot of faith in Harry's rumors.