Even Don Draper would have trouble selling a $3 can of Coke. For years now, Coca-Cola has wielded some of the strongest pricing power in the entire consumer business, steadily raising the prices of Coke and its other sodas while hardly shedding customers. But as the company nears its fourth-quarter earnings report this week, executives, analysts and other onlookers are beginning to wonder if shoppers are finally nearing their breaking point. SUBSCRIBE:  Receive more of our free The Daily Upside newslette ...