Gentoox

http://gentoox.shallax.com/
https://en.wikipedia.org/wiki/Gentoox

First release -unknown-
Last release 1/2009

Wikipedia:
Gentoox is an operating system based on Gentoo Linux, created 
especially for the Xbox by Thomas Pedley. Gentoox requires a modchip 
or a software mod to run, as it is not authorized Microsoft software.