I've been searching for badge shapes for Pixelmator Image Editor but I couldn't find what I need. For this reason I've made 28 shapes for myself. There are badge, shield and ribbon shapes for free. I hope you like it. I don't know how to make a .pxs file so all shapes in a .pxm file. If you want you can select one of shapes and you can add shape into your shape window. Or you can just drag layers into your project. Sorry about that.
Also check http://pixelmatorshapes.com/ for more.