I know I know, Greater Sanctuary is not perfect in NWN 1 ... but in NWN 2 there is this spell for clerics
It is a 9th lvl spell and called " Etherealness" in nwn 2
I could see how Noss (my PC) would use it ... taking donations to Dorand in Lar, passing the Ogres in the Grey Peaks without a fight, especially when he is encumbered and can not move with easy.
in nwn 2 manual "etherealness" is decribed as ... Enemies cannot setect the party until any member performs a hostile action.
Just an idea ...