I just found a new air staff skin in Abaddon's Mouth Mission while killing bosses. (I am pretty annoyed because my router reset and err7 when I was about to complete bonus.)
Perhaps other skins have been added as well. I know for sure Shadow blades have been.
New Skins?
LifeInfusion
Esprit
With the streaming updates for Faction content, new skins have been seen. There are a few threads around with pictures.
Lasareth