[Al Skierkiewicz]

Before we all get out of control here...
Most remotes have a either a transistor switching current to the LED or the output of the encoder drives the LED direct. Regardless of the design, the LED has a series current limit resistor to set it at the correct forward operating current. If you were to put LEDs in parallel, the added current across this resistor will raise the voltage drop across it, in effect sharing the current between the two. You could add another series resistor for each LED but you could still damage the remote control's output stage which may not be repairable. But there is still another problem in your way and the reason that remotes generally don't carry more than one LED. Think back to your wave tank experiments in Physics. Two emitting devices will cause interference where sometimes the waves will entirely cancel out and others where the waves will add. The position of the interference is relative to the distance between the two emitting devices and their individual radiated signal. Your best bet is to experiment with the remote you have and see what the effective distance is. My Sony universal can change channels from upstairs if I aim it at the wall in the stairwell. That is reflecting off a wallpaper surface and hitting the TV at an angle at least 45 degrees off axis with a total path loss of at least 30 ft.