Actually, the assassin's blade quest works for me. Over & over. So now I have several Druss Blades in my current .952 campaign. You have to kill the innocent good guy and return to the quest start point. Not sure, but I suspect you may still have to be carrying the assassin's blade when you come back -- might be a mistake to sell it or hand it off to another champ.
This makes it one of the best quest scrolls around. Repeats, not dud. And the Druss Blade is pretty good.