I can run a 3rd coax from the dish to the coax that's feeding my bedroom and then put another receiver there. But if I do that, I lose access to my living room TiVo... Don't want to do that.

Another thought: for the short term (now until December), you could do exactly this. It will be cheap and high quality. In December or thereabouts, TiVo may finally ship the HD-DirecTiVo. At that point, the HD-DirecTiVo would go in the living room and the old DirecTiVo could migrate to the bedroom. Then, the only question is whether you can put up with TiVo fan and hard drive noise in your bedroom.