Heard about this on http://dl.tv today. It’s a binary gentoo build that has all the xgl stuff configured and the nvidia/ati drivers with it on a bootable live disk. So all you have to do is boot from the CD and you can start playing with XGL. Really cool stuff.
http://kororaa.org is the distribution, here’s the link to their download page for the xgl live disk: http://kororaa.org/static.php?page=static060318-181203