One known PH is among the adherent NPCs in Borgar Rompinstomp's area (specifically -287, +1293 -- the second dwarf from the left when facing the camp from the Underquarry zone).
I got this guy to spawn at the above loc. The PH/Ragbeard is the second from the left. He's on the far side of the table, so he faces the Underquarry zone.