The find option sucks. I tried using it while standing right in front of him and it did not work. He is near the other vendors in the area that sell things. I didn't think he was cause find didn't work right in that area the first time. So i thought maybe he was in the temple with some of the quest npcs but he wasn't. Hopefully the find thing will have been fixed by the time you read my post.
[Fri Jan 14 03:27:14 2011] Trader Thallynus tells you, 'That'll be 11 platinum 2 silver 4 copper per Spell: Katta Castrum Gate.' [Fri Jan 14 03:27:14 2011] Trader Thallynus tells you, 'That'll be 26 platinum 2 gold 4 silver 9 copper per Spell: Katta Castrum Portal.' [Fri Jan 14 03:27:15 2011] Trader Thallynus tells you, 'That'll be 52 platinum 4 gold 9 silver 9 copper per Spell: Translocate: Katta Castrum.'
This trader is located at -720.15, -362.00, -103.47. Located outside the Temple.
When using the guild hall portal, exit the temple go East then South. You will drop over a wall which will bring you nearly face to face with this vendor.