So while I was up at my local GW I was talking with a Red Shirt and Black Shirt. I purchasing a Inquisitor and the guy asked if I new the Plastics for the GKs were coming out soon. I asked if that was now confirmed and he said Yes. I asked when, and he told me that they had beat out DE for release, but that DE was also confirmed as arriving by Christmas.
Evidently the information comes from a conference out in Las Vegas.
The facts I know from the conversation.
1. Inquisitor Dex will arrive before DE
2. DE by Christmas
3. Inquisitor Dex will be after 8th Ed Fantasy
4. One Codex to contain all Ordo's, Malleous, Xeno, and Heriric
5. Sisters will not be present in the Dex, but will have there own Codex at a later time.
6. Deathwatch/Alien Hunters will be present
Other info based on them not actually getting to see the Codex but talking with the people, sounds like you'll still be able to build a pure GK army, and sounds like it will be more useful. Points Drop on PAGKs, TGKs to stay about the same point cost but be better.
That's about all I know for now, more info to come as I get it.