An update of ruby-gettext to a recent version (1.4.0 currently) would be nice. Currently portage contains version 1.0.0 of ruby-gettext, which lacks some features for rails applications (like scanning sources to automatically create and update .po files). I was able to successfully emerge and use ruby-gettext-1.4.0 by copying ruby-gettext-1.0.0.ebuild to ruby-gettext-1.4.0.ebuild.
Thanks, bumped in portage.