Stop for a minute and think of some of the most successful German companies. BMW and Siemens and Bayer might come to mind. But if you really want to learn from the best of German business, you’d be smart to turn your attention to companies named Rimowa, Jungbunzlauer, and Strama-MPS. They belong to a class of small-to-medium German enterprises that are outperforming the country’s top public companies.