I just want to add to this thread that I killed over 1500 of those priests in Mana Tombs using my Druids to stealth in and kill them and reset(feral/resto took forever to kill them) and the enchanting pattern never dropped. I have screenshots of the fubar addon that tracks the mobs you are farming around somewhere.

I go in on my Pally/Shaman team and the first priest pack I kill drops the pattern! :cursing: