Decided to post about my ATX to Xbox adapters as i've been contacted about them a couple times now.
I won't build more of them in the future as it's quite a time consuming process but you can order the PCBs and build them yourself.
The bill of materials is printed on the bottom layer and assembly is pretty straight forward too.
The solder work isn't hard to do so even a beginner is able to get it done!
You can order the PCBs here:
Rev1.0-Rev1.1
Rev1.2-Rev1.5
The ATX Port and Cables can be reused from a dead (or unused) Xbox PSU and motherboard. The end result might look like this 2 examples here: