I think that's an idea with a certain panache and utility together. For instance, some metal plaques to the same design as our badges. But I expect that would cost a lot more than badges! And persuading cafes, hostelries, even bike shops to display them might not be as easy as in days of yore. Finally, would they require planning permission? Much easier and cheaper, even though not so classy or long-lived, to produce stickers.