I'm trying to replace my pair of shabby Tieks at the moment, and just tried out the Miu Miu buckle ballet flats.

My review of them is here, but basically, if you have wider feet or bunions at either end of the size spectrum, or very low volume feet, it might be worth giving them a shot. They are ridiculously expensive, but if you know your size in advance, you can set up alerts on online consignment stores for them to appear.