Yep, I ran smack into that problem on Thursday's update. Took me a while to fix stuff: /etc/conf.d/net and having to remake the link from net.lo to net.eth0(net.lo itself now seems to be a link to some script ...). I don't know what else is still wrong.
Thanks for pointing out the baselayout upgrade as the "culprit". I'll take some time to "read the 'fine' manual" at
http://www.gentoo.org/doc/en/openrc-migration.xml before Monday.
Cheers
Riaan