A quick heads-up if you upgrade to the latest udev in portage. Don't do what I did and postpone the etc-update step till later, forget about it in the rush of trying to get work done, and then need to reboot. When the machine boots, sysfs does not mount, the proc init script fails and everything thereafter fails.
I suppose it's possible to boot into single user mode and manually edit the files in /etc. But in my case it was not at all obvious that this was what I had to do. I had to boot off a rescue USB stick and chroot to see what was happening. -- alan dot mckinnon at gmail dot com
