Deathwing and Ravenwing Detachments are in these leaked images, and you can clearly see up to 12 elite choices with Deathwing and 12 Fast Attack for Ravenwing. However, these leaks are in German, so I cant make much out of the special rules.
From my own Initial look though, Deathwing looks like a great allied force, as does Ravenwing. There are lots of options, including fomations for both. I am still looking for some translations or English versions as we speak.
via Timotheus on Bolter and Chainsword
http://www.bolterandchainsword.com/topic/303857-rumours-dark-angels-2015-codex-leaks-pg-62/?p=4097448
Some Translations- by BT_Cennar
Ravenwing:
First Hunter (Erster Jäger): You may reroll warlord tallent.
Fast as the Raven(Schnell wie der Rabe): Durring your first round(or 2nd if you placed all your Ravenwing units in reserve) all units from this contingent use the jink and turboboost speacial rule.. Howeever this units are allowed to use their full BF and are not forced to Rapid fire in your next turn.
Joined Attack (Vereinter Angriff) : All units from that contingent must be placed together at reserve or at the Table. If placed in reserve they all arrive automaticly at begining of your 2nd turn.
Deathwing:
Bring the fight to the enemy: Durring the shooting phase ,that turn those Unitis arrive via Deepstrike, the units may choose to Shoot and than to Run, OR Run and then to Shoot.
First Knight of Caliban: If this Contingent is ur main Contingent you may reroll your Warlords Tallent.
Called to Fight (Called to Arms?):All units must Start in Reserve If your Army enclose either a Ravenwing Attack Squadron or a Ravewing Strike Force you may choose to either Automaticly fail or pass the reserve check, its not neccessary to roll the dice.
More Leaks by Timotheus
Formations including Battle Wing Demi-Company, DW Redemption Force, RW Attack Squadron, RW Support Squadron, RW Silence Squadron
http://www.bolterandchainsword.com/topic/303857-rumours-dark-angels-2015-codex-leaks-pg-62/?p=4097486
More Leaks, Belial
http://www.bolterandchainsword.com/topic/303857-rumours-dark-angels-2015-codex-leaks-pg-62/?p=4097528
The Hammer of Caliban and all the Unit Entries
http://www.bolterandchainsword.com/topic/303857-rumours-dark-angels-2015-codex-leaks-pg-62/?p=4097600