I did do something similar myself a few years ago. It wasn't a TV, it was a satellite receiver box. I already 'piped' the RF output around the house to TVs in different rooms by combining it with the antenna signal and feeding it through a distribution amplifier but with that blocking the return path it wasn't possible to remotely control it. I duplicated the IR driver stage and ran a pair of thin wires to a second IR LED in the room with the box so it could be sent commands from elsewhere. It wasn't the most 'universal' solution, being tied to one remote unit, an IR repeater would have been a better solution but at the time I was virtually immobile and a dirty but quick solution was best.
Brian.