The pattern is currently only for a size small but I do plan on adding a medium and large in the near future. You can buy the fat quarter at spoonflower.
I have made my own short stays from this pattern (with modifications because I'm not a small person) and LOVE them. I actually have two pairs. Here's the red pair:
I don't think I have a picture of the blue pair, but I wear them with pretty much every single Regency gown I've made. The blue pair are a bit hardier because of the fabric I used. If you have any questions, feel free to ask.