Ford's commercial business is blossoming, and GM has taken notice. They say imitation is "the sincerest form of flattery that mediocrity can pay to greatness," and that might be playing out between Detroit's two largest automakers right now. General Motors (GM -0.33%) has seen the success of Ford Motor Company (F -1.15%) in one specific aspect, but can it copy that? What's Ford doing? A decade ago, investors almost viewed an automaker's fleet and commercial business as dirty work. This segment was seen as a ...