With v18.45.16 Update, new stance books have been added to the Stance Promotion Recipe Shop at the Master Guardian. T3Fun's server would probably get this in the next update, so if you are thinking of spending a bomb on the following stance books, you may want to think again.
|Screenshot taken from Singapore server (v18.45.16)|
Promotion Recipe - Stance is available via the weekly Black & White: Temptation of Darkness quest. See Viron Quests for details.