I don't know if the T3 is special in any way, but I can use my T3 just fine from the same distance as the regular remote control, the only difference is that I have to be a little bit more accurate when pointing the T3. 5 meters (~15 feet approx.) works fine, if I just point it the right way. I'ved tested with Panasonic TVs by the way (it works equally fine with other people's Panasonics.. to their amazement)

I also know that Palm owners have been using their PDAs to switch off annoying TVs in pubs and the like.. so it's got to work over that distance as well.