Yeah, that's the exact idea that my Oracle suggestion was. I'll repost it again soon.
howbout an indepentent character that knows what everybody's role is from the beginning and has to manipulate everybody so he/she will be the last person/live a certain amount of days
I do like the Beggar role better than the Oracle though. B/C then the character doesn't know who everyone is from the beginning, and the Beggar must make sacrifices, rather than just wise decisions.
BTW, just to clarify, the Psychic can choose to do that for any night time action, not just the Spy and a killing (those were just examples). They could also deny the Thief, or the Bomb Lie-detector, or the other things like that.