After watching the sleeper Xbox Build, I haven't been able to let go of the idea of replicating the build. I have access to a machine shop this semester (Solid State Physics Lab class! Whoooo), and can most likely CNC the liner from the CAD files they provided in the description of the video.
But it seems there was a LOT that kind of got yada-yada'd over. How did they wire the power button from the Xbox chassis to the ATX power pins on the motherboard? Did they just swap out the hardware for some other pushbuttons? How about the USB (2.1? 3.1?) ports in place of the xbox's proprietary controller ports?
I have a dead Original xbox just rotting away in my closet, and I would love to have a sleeper for some couch gaming with my girlfriend. I'm still figuring out the exact hardware I want to use, part of me is thinking of just getting a NUC and mounting it alongside the internals of an EGPU inside the xbox chassis. But that still leaves the problem of the power switch and USB ports.
In an ideal world, I'd 3d print or otherwise mount a mini-itx mobo tray inside the xbox, with some sort of solution for a gpu bracket as well (that doesn't involve hacking a port off), with the Xbox power and eject switches wired to the motherboard's power and reset connectors.
edit since I forgot: To make it a hardware and software sleeper, once it's configured, I would use Windows 10 Pro's group policy editor to disable Explorer.exe, and instead force it to load steam.exe on startup, with flags both in steam settings and GPE to start steam's big picture mode on boot. I would also disable user pw and have it auto-login (the only thing loaded on it would be steam, and the windows account would be a local account, not a Microsoft account). Origin, Uplay, and GoG games would be loaded through the steam launcher.