Allow me to finish the job of refuting the pole analogy.
True, it is easier to lift a 10 pound pole from the center than from one side. This assumes that the mass of the pole is evenly distributed, which is generally the case with poles.
However, the mass is most definately not evenly distributed in any rear engined aircraft (such as DC-9, MD-80, MD-90, 717, 727, BAC 111, F.28, F.70, F.100, Tu-134, Tu-154, Tu-334, Il-62, VC-10, CRJ, ERJ-145, Caravelle, etc). The engines are very big and heavy, while the fuselage itself is relatively light (remember it's mostly hollow). Thus the center of gravity for these airplanes is not in the middle of the airplane, but towards the rear. Thus the place that it is easiest to lift is towards the rear.
Imagine that your 10 pound pole did not have it's mass evenly distributed, but was hollow and weighed three pounds, with a seven-pound weight glued into one end. Suddenly the easiest place to lift the pole is not in the middle, but like our rear-engined aircraft, towards the rear.
You also ask why the stretched fuselage of the MD-80 does not have even more of a problem. The answer is simple: The engines are heavier. The Pratt & Whitney JT8D-217C and JT8D-219 engines weigh more than the JT8D-5, JT8D-7, JT8D-9, JT8D-11, JT8D-15, and JT8D-17 engines used in the various members of the DC-9 family. Thus while the fuselage was stretched forward of the wings, the added weight of the engines aft of the wings compensates for this.