Here you can find the Gerbers for the corne-xiao.
The pcb has the same dimensions and mounting points of the corne-cherry by foostan. So it will work with all the corne cases with the following constraint : Since the controller is mounted facing up and is different from pro micro, make sure the case has clearance for the usb port.
Corne v4 plates/cases will not fit as it has different spacing from the previous versions.
I have also shared files for a case that I personally use here.
While the build process is similar to most of the keyboards, I have shared a guide with some images and details of the parts here.
You can find the zmk-config here. ZMK Studio support is enabled by default. Ensure you flash the v1 firmware for the Rev1 PCB and the v2 firmware for the Rev2 PCB.
By default, the firmware uses a zmk-rgbled-widget made by caksoylar to help with the bluetooth profile and battery status. In case you don't want to use the widget, you can remove the keyword rgbled_adapter from build.yaml.