The latest PTR 3.3 build 10571 introduced new models for two bosses in the Icecrown Citadel: Pit of Saron 5-player dungeon.  Krick used a standard Leper Gnome model, and was changed to have a unique model with a white punk hairstyle.  Scourgelord Tyrannus had a generic helmet similar to the one hanging by chains above Dun Niffelem. He now has a unique armor set.

KRICK NEW MODEL

   

SCOURGELORD TYRANNUS MODEL