gnome-2.22.1 fails because gst-plugins-base-0.10.19 is not in portage. # emerge gnome These are the packages that would be merged, in order: Calculating dependencies | emerge: there are no ebuilds to satisfy ">=media-libs/gst-plugins-base-0.10.19". (dependency required by "gnome-base/gnome-2.22.1" [ebuild]) The better question is *why* the newest version of gst-plugins-base in portage is 0.10.17, given that 0.10.18 was released a month ago and 0.10.19 a week ago... (see bug #214286 - it has zero dev response so far)
This is one of the reasons gnome-2.22.1 meta is currently package.masked. Don't unmask it, the rest (including gnome-2.22.0) is already unmasked for you in x86 and amd64.