I think it'd be pretty cool if there was a quest, or maybe a few, that rewarded you with 100AP! This could be a potion or so, so maybe it could be sold later on, or just a reward to the player and not an item!
As for the quest its self, I'm not quite sure what could be done, but if there were quite a few of these quests then people who lose their 100AP could do it again - although maybe just a one off would be better, so that it's a choice whether or not you want to do it there and then.
Could be a simple collect various things, or theme it around holyness and spirits or something! I don't think there has ever been a quest for such a prize, and I feel quite a few players would love that quest reward