Please remember that these are rumors. Salt Required.
Here is a link to the first set from Whitehat.
http://www.natfka.blogspot.com/2012/06/6th-edition-rules-assault-distances.html
via Whitehat
Preferred Enemy: Reroll hits in CC & Shooting AND Rerolls 1 to wound.
I've checked, Black Templars vow, accept any challenge only gives Preferred Enemy in combat (damn)
The Pancake rule set is mainly wrong, but there is a lot of stuff that made it into the final product.
Expect FW to put out a book of there flyers but with added 6th Ed goodness.
I mistyped the cover saves. Ruins are 4+, the vast majority of stuff is 5+
I did not mistype WS1 for moving vehicles, they are not WS10 if they moved - flyers might be different; not sure.
Preferred Enemy change of reroll 1's to wound is in addition to current rules for Preferred Enemy
Flyers are noted in the BRB changing some of the existing vehicles (Summary sheet in the back)
Eldar Flyer, Void Raven and Tau I believe are in the same wave.