Along with my "slim" case I have also created a "mini" case design, well two actually.
The first one utilises 2 oled displays on top, has an acrylic tinted top panel that hides the bezels, the second only has one oled on the front but can be 3d printed in just 2 parts.
Both require a pico psu (unless someone can make a pico sized xbox psu lol) and an ATX to Xbox adapter.
Here's a video of how the dual OLED displays look: