Even before armies used tanks, they were using motorcycles. In 1916, US troops on motorcycles chased Mexican bandit Pancho Villa (who also used motorized bikes in his raids). In World War II, couriers zoomed all over the front carrying messages, while German reconnaissance units even used sidecar motorcycles armed with machine guns. Today, US special forces use motorbikes, including some commercial models.Motorcycles are fast, nimble — and as actor Steve McQueen showed in the World War II movie "The Great Escape" — the epitome of cool. But replacing tanks with motorcycles? Skeptics might prefer to trade coolness for the security...