I just wanted to share/show off my first build. It's an original GB Null from Ampersand with a 3D printed case an custom PWM audio.
Unfortunately I forgot to take the final pre-case-closeup pictures, therefore the audio is not yet wired to the Pi on the respective picture.
I've been using stereo audio with a PAM8403, a 1000uF decoupling capacitor and some smartphone ringers/buzzers. The stereo filter is the one described by SP33 in his fabulous (PWM audio guide post ) implemented with a custom minimum-size layout including a ground strip.
I also decided to include one of the cheopo battery status indicators one can find on eBay/AliExpress .
The screen lens/cover was made from 2mm acrylic glad.
The case  was wet-sanded with 120 to 400 grid sandpaper, then primed with 2 coats of spray filler  and finished with 4 thin coats of nitrocellulose lacquer spray.
It was a really fun and easy build thanks to Ampersand and all the great resource on this forum.