The secret convertibles built by Ford and GM continue to be frozen out of the North American market for reasons that are vague. The German built Ford Focus drop top (left) and its similarly sleek GM counterpart, the Opel Astra (right) are non-gratis here. It’s doubly odd because the German owned auto makers (Mercedes, Audi, BMW and VW) all eagerly ship their cabriolet models to North America — and do very well with them thanks. But the magic advertising juice of “German Engineering” apparently has no sell in the corporate headquarters in Detroit. Why? It may have to do with GM and Ford being intent on selling their muscle convertibles, the Mustang and Darth Vader-like Camaro Remember the old saying: “You can sell an old man a young man’s car.” That’s what seems to be at work in Detroit. But, as sales of the German owned cabs show us, there is an incredibly large market for these types of vehicles.