Impervious have been through some bosses of Hyjal Summit, with a little help from a Gamemaster death touching the bosses. I'll just list the most important screenshots, you should check out their site if you want to see everything.
You will notice that the mace dropped by Kaz'Rogal is the "tier 5" one we posted a few days ago (click on the right for a bigger version), we can now assume that all the classes weapons included in the 2.1.0 game files are drops from Hyjal bosses.
Rage Winterchill + Loots
Kaz'rogal + Loots