Seeing through walls at a distance

Great, when used responsible. Horrible if used for evil. [Link]

For the last couple of days, in the Human Nature blog, I've been looking into a breakthrough cryptically reported in Iraq and Afghanistan: the ability of U.S. unmanned aerial vehicles to identify and track human targets "even when they are inside buildings." Several recently reported technologies might account for it, but Slate reader fozzy suggests looking for the answer in a military research field called STTW, usually translated as "sense-through-the-wall." Has this ability been extended to a distance that allows it to be used by aerial drones?