Your challenge is for the Holy Roman Empire as a whole (or at least, a very large portion thereof) to form a government similar to the Swiss. Basically, if we could recognize it as a sort of federal republic on a broad level, it counts. That should provide enough leeway, I think. Your only restriction on timing is the lifespan of the Holy Roman Empire itself, broadly defined; Charlemagne to Napoleon.
But, don't pick Napoleon, please.