I was told that to avoid ransacking an end reward you should do a quest, then see if you get a sigil for it, then if there's no sigil you don't take ANY reward, close the reward window and abandon the quest. That way you can farm a quest for as long as you can without having it ransacked.
And there is something to it, when I've done the church and the cult again after a long break I've got +1 tome, the best quest reward I've seen so far (gold sigil would surely beat that!)
Edit: On a second though, it is quicker to do Mirra's Sleepless Nights in house J. Some people think you need a rogue for that but it's only the case if you're stupid enough to approach the trapped chest. You just need to fight like 3 undead in the first room, then go see 2 noisy golems on the left side (again like 3 undead on normal) then back to where you start, go north and going near the wall leave the room through the door to your right. 2 more mobs and the quest is finished, you dont even have to fight the ghost-boss.
Sorry if this description is over detailed to the extent that it may offend but I already heard too much crying over this quest ("maaan we should have got a rogue, you suck and so does your group, waaah, repair bill, waaaaah")