Well, we do change MC alignment from neutral to something else. While it shouldn't be possible to change it freely and anytime, the option should be there, I think.
It even could be two separate quests. The early and easy one is to obtain alignment, and the difficult optional quest is to change it if player changed his mind.
While I have some good icons for spell books and scrolls, the current item system doesn't support it I'm not mistaken. Although, we could handle it another way: you could find a spell book, but you need to bring it to a Mage Guild to learn the spell.