Thanks to everyone for posting Mary's shoes. I absolutely love them (except for the snake-skin ones :(). The shoes (from the link above) are so nice. I have looked for shoes like that (more of a 1920's style though) but I've not had much luck.
I was looking through this catalogue* that came this morning, and I saw these shoes that I absolutely loved (too bad there’s no place for me to wear them :p). I then thought that they would suit Mary; she often wears similar shoes. I scanned the page, but it hasn't come out that well. Sorry! They are by Manolo Blahnik who, as it turns out, also designed Melania Knauss' wedding shoes.
* If you are Australian, you will see them on page 5 of the Myer Winter Collection catalogue.