Seems to me that someone could make a small circuit to emit the same IR frequency the bar does normally, and place it inside the bar, along with a power sourse (batteries).
After I played around with it a bit, I did find out that it's a steady frequency, no variances to complicate matters. Well, except when you calibrate it, it flickers a little bit, but that's not really important. Really, it probably doesn't even require a specific frequency, you could probably just make some really basic flickering timer circuit (just to save power), so long as it's stead enough to keep the pointer on screen at all times.
edit: Looks like the sensor bar only uses 12V DC. That is, going into it. I don't have tri-wing screwdrivers small enough to take it apart, so I don't know what it is across the LEDs.
Did you look at the waveform on an oscilloscope? If so, I'm interested in the details. If not, I may just bring my oscilloscope home tonight and see for myself.
From looking at the picture that dirtie posted, and some general assuming, I would say that all 10 LEDs are wired in series giving about 1.2V per LED. From my experience, that is actually a lot of voltage for a run of the mill LED such as these. You could always make your own by wiring in parallel or a combination to make it whatever voltage you wanted. If they sold sensor bars separately, I'd actually take one apart, figure it out and try to make my own.
