I just read the blog and comments at: http://aaronbock.net/journal/index.php/entryId=6:24 and check my gentoo system to find out that there is /etc/gentoo-version only. It would be nice to have an lsb_release command too. (though I have no idea how much gentoo is lsb compliant)
the lack of a lsb version file or lsb_release command should imply that we're not lsb compliant in the slightest