I have always wondered this, but never been able to find an answer. In Port Llast, just to the North of the Temple of Tyr, beside some gravestones is a locked door.

The door is un-bashable and the pick lock difficulty is like 100DC. Is there a key for this door and if so, where is it?

(I was feeling self destructive and narrowed the choices down between jumping infront of a bus or replaying through the NWN OC. NWN seemed a much surer bet to cause massive damage)

I don't understand why it would make you feel self-destructive. To me the OC just isn't worth the time; I never got past Chapter 2. Get SoU and HotU and play those campaigns instead.

I have SoU and HotU, just decided to play from Level 1 starting in the OC.

Does anyone have an answer to my question?

I don't think it's any more than just a piece of decoration. According to the Toolset the door leads nowhere anyway so it's pointless to open it.