To add to Vessbot's post, on a large aircraft the radius of turn made by the extremities (nose, tail) will differ to that of the CoG and have noticeable effects, compared to a small aircraft such as a Chipmunk. If the slip/skid was of a self contained type, as used on light aircraft, and installed in a large aircraft cockpit centering the ball would mean everything aft of the cockpit would be in a skid. IMHO