Too far for an IR LED, you might have to go for lasers.
If it's not too far then it certainly is borderline. How far does your TV remote reliably work?
Adafruit sells a device that transmits only the "OFF" code for every tv code known. You could use that and a photo... what a waste...
Actually you might use this as a starting point since the TV-B-Gone (TV-B-Gone Kit [Universal v1.2] : ID 73 : $19.50 : Adafruit Industries, Unique & fun DIY electronics and kits) is fairly high powered in order to get enough range so that the user does not get assassinated by his victims. I would salvage the receiver out of an old TV, DVD player, etc.
Don