I've been Googling all over and haven't found any XML versions of the Mirror API templates. I know that the Mirror API allows you to see the HTML and CSS associated with these cards, but since I have to use the GDK in my application and can't use the Mirror API at all I cannot use these templates. I feel as though this is something that should be provided in the GDK but currently isn't. Are there XML versions of these templates released by Google or someone else available for use?
The CardBuilder class in the GDK provides many of the same layouts in the Mirror API Playground without the need to manipulate XML directly. Try to use those whenever possible to ensure a consistent Glass user experience.
If those don't meet your needs, you can also find copy-and-pastable stub layouts in our developer guides, which already have the proper margins laid out for you.