Not really surprised that nothing has yet turned up. Descent from altitude after a catastrophic event, either in large or small pieces, would be subject to trajectories influenced by, amongst others, the forward motion of the aircraft, the force of whatever caused the catastrophy and wind, which could scatter debris over a wide area well away from the point of the event. In effect we are back to basics once the aircraft fails to be a complete unit and the fact is the area to be covered can be thousands of square kilometres.