The Tiny Tina's Assault on Dragon Keep head customizations are finally being released, as SHiFT codes of course. So yea, you can't just finish the DLC to get them, like with previous ones. You have to make a SHiFT account so you can put the code in in-game. They're being put out one per day.
Axton - Warrior of Light (
screenshot)
PC/Mac - KJKJT-WHBKX-HC9BT-TJBJ3-XJFSJ
Xbox - 5JK3B-S6KTB-5BB5X-CRTBB-FC3ZK
PS3 - CBKJ3-XTXFW-5KRCJ-9J5BT-J3SRH
Gaige - Wayfarer Wizard (
screenshot)
PC/Mac - CBKBJ-6ZJW6-HKH3T-B3T33-F5ZRS
Xbox - KB53B-TH5BB-KBB5R-WXT33-6HR9R
PS3 - KTKTB-HTXFW-KK6CT-SB5JT-3R6XZ
Zer0 - G0ry Gh0ul (
screenshot)
PC/Mac - CT5BB-XTW5X-9CSBT-3BTTJ-FT5X5
Xbox - KB53T-3T6JB-W3T5F-K6B33-Z9W5R
PS3 - 5T5BT-ZKRRC-556WB-9TWJJ-ZXWWH
Maya - Elven Eliminator (
screenshot)
PC/Mac - KTC3T-WTW5F-ZCHB3-BT3B3-XJ9WR
Xbox - 5TC33-9Z5BT-533WR-W63BJ-66WJW
PS3 - CJ5JB-RCXFK-K5F53-9TWTT-SKZZF
Krieg - MY EARS ARE RINGING (
screenshot)
PC/Mac - CBKBB-ZHJC6-SWHJT-JJ3BB-3CXHS
Xbox - K3CBB-CHWBB-WJTWF-WXBB3-K3KBK
PS3 - 53CJT-35FFK-WK6KJ-9J5BB-HFJX6
Salvador - The Beast Within (
screenshot)
PC/Mac - WBCJJ-33KWR-S5Z33-BJTTB-65WJJ
Xbox - KBW3J-F95TT-W3JKF-WFTBT-KF6XX
PS3 - 53CBB-KKFXC-W565T-Z3C3B-SKJ33
The associated skins are coming at a later date. They said one of them has an issue and the game needs to be patched to fix it. (I've seen screenshots of some of them, and yes, Krieg's skin doesn't show up properly)
EDIT: By the way, if anyone wants an easy place to keep track of the codes as they release (and in a text format so you can highlight and copy, unlike the images they use on gearboxsoftware.com), check this link out. Even if you're not using it repeatedly to keep track of new codes (I check it daily for new golden key codes), it's a good place to get a few dozen golden keys from the old codes that are still active. There's some old item codes on there too.
http://orcz.com/Borderlands_2:_Golden_Key#Latest_Shift_Codes