Wowza- love these pettipants. I have a couple pairs and I wear them when I know I'll be twirling or just to give me a little extra sass. The ones pictured are available at one of my favorite etsy stores called Cheapfrillz in the pettipants and panties section, along with a dozen or so more lovelies like this.
They range in price from $20-39 and the sizes are basically medium, but they stretch to go up to a waist size of 48-50" and leg size of 27-30". I would suggest using your thigh measurement to see if they would work for you. If you need a bigger (or smaller) size, you can request a custom order through Cheapfrillz etsy store. Please allow up to 6 weeks for custom work.