The Ruiz Brothers made this real nice case for the iPad Pro 11″. I have been using one on mine since I got it. But it was missing the cutouts for speakers and microphones. I was able to find the Apple Accessory Design Guidelines and get the dimensions and placement of these items.
Using the Fusion 360 files provided in the Adafruit Learn Guide I was then able to add these features. My remix of the design is available on Thingiverse if you would like to print it.
