Heh, triple posting.
About the quest rewards:
Katehos could give you the large and mysterious saga of the pantheon written by prof. Kaethos, Ph.D.
(inspired by CLIVAN, of course). The book is unique in the same way as belt of levitation - you can get it from the quest or wish for it, but it cannot randomly generate. The book can be read only once, revealing the rituals of all gods to you and heavily training your Int and Wis. As you will be rather far into the game by the time you trigger Revolution (and before you cannot complete the Kaethos quest), knowing all god rituals is not overpowered in my eyes. The stat training is and added bonus.
When you finish the Silva altar quest, the priestess could give you the horn of plenty
- again, a wishable but non-generating item. Each time you apply it, it will create one piece of random fruit (banana, pineapple, kiwi or carrot, never holy banana). Given the time it takes to recharge, it cannot sate your hunger on its own, but it can save you while starving and serves as a way how to eat fruit without the fear of it spoiling.
And once more about the Mistress quest - I just found out that Petrus' wives in vanilla do not wear chastity belts
. And that's sad.
I'd be for porting chastity belts with one improvement - in CLIVAN, they cannot be locked even though they do have a lock on themselves. So what about making the chastity belts lockable - you can equip or unequip it only while unlocked, locked chastity belts will stay on your groin until unlocked or broken. All Petrus' wives are generated with locked chastity belts with octagonal lock and you have to get an octagonal key to bump uglies with them.