Actually the T6 Token are traded in at a Vendor in Hyjal Summit. His named is Tydormu.

The tokens are dropped from these people:

Gloves - Azgalor, Hyjal
Helm - Archimonde, Hyjal
Shoulders - Mother Shahraz, Black Temple
Legs - Illidari Council, Black Temple
Chest - Illidan, Black Temple

Good Luck even if you down one of them you'll need to win roll =(