It seems to be coming from the passenger side, though it is hard to tell. All four wheels had brake pads and rotors replaced two months ago, so that shouldn't be an issue. Obviously I'll need to have a pro look at it, but I wont really have time until mid January (unless this becomes an emergency issue). I would imagine that it is indeed something torque related (as opposed to rpm), since it does not occur on the highway regardless of rpm.