I think Open SUSE would be a good next try, it's very GUI driven, so the installation process would be similar to Ubuntu. Note that apt-get will not work in SUSE, but it has it's own package management and repository system.
I'm giving up on Xubuntu, it seems to not be the answer.
Gentoo is more for relatively experienced users, and same with Arch. By advanced, I mean there's more manual work in the terminal.
Manual doesn't scare me, but it looks like installing is a bitch. I tried Xubuntu, but the installer wouldn't format my USB. Probably going to try and do the kernel lock tomorrow morning.
What happens if you switch around the pci ids in xorg.conf, say to make 6:0:0 correspond to Device[0]-0? You can get the order linux believes the cards are in using,
I'll try it in the morning, I'm exhausted.