"The reason for the limited reception range is that receivers use pathetically small, internal antennas: Mine was about 1/32 wavelength. With a full wave antenna or directional antenna, you can easily pick them up from outside a building. After I added a larger (1/4 or 1/8 wave) antenna to my receiver, I could type with my keyboard outside the house."

So, in theory one could hack the receivers to make them bigger and perhaps account for drift and make them more reliable at anything further than 2 or 3 feet.