Tain Hammerfrost in eastern wastes for coldain ring 4 doesn't seem to be respawning. Did the quest like 5 hours ago, and while I was doing it he got aggro from a wandering orc, who hit him, then he vanished and hasn't been back up since that I've seen.
On live he was a few second respawn, and:
http://everquest.allakhazam.com/db/npc.html?id=13270
"I just did the quest and unfortunatley I let Tain get killed. So thought ok come back in a few hours and do the turn in again. But I looked up when the giants despawned and Tain had respawned."
Edit: This is on Red by the way