Lylirra
Dragonwrath, Tarecgosa's Rest does have a proc, but the information hasn't been included in the PTR data files yet (which means there's nothing to datamine right now).
We did, however, hint at what the proc will be in our 4.2 preview:
http://us.battle.net/wow/en/blog/2685003The great staff duplicates destructive magics, and also bestows upon its wielder the ability to transform into a member of the Blue Dragonflight.