The SIO2PC has been around for over 15 years has expanded to include a USB version and a Dual SIO version, none of these come with a case. I have designed cases to fit all the different boards and close with two M3x12 screws.
https://atari8bit.net/projects/3d-printing/atarimax-sio2pc-cases/
The author marked this model as their own original creation.