As cairo has become a general gfx output library and some utilities have begun starting to use its svg and pdf output, it would be nice to pkgmove cairo away from under x11-libs. This would specially nice for server environments, which might be using rrdtool but prefer to remove x11-* from portage tree. There are some other roadblocks too, as cairo depends on x11-libs/pixman.
Is there any real advantage to this? Because changing all the depends and making the package move would be a lot of busy work. I honestly don't see why you delete x11-* directories since they use a relatively small amount of space and potentially break your dependency tree.. % du -hsc /usr/portage/x11* 2.0M /usr/portage/x11-apps 771K /usr/portage/x11-base 3.4M /usr/portage/x11-drivers 4.0M /usr/portage/x11-libs 5.5M /usr/portage/x11-misc 4.2M /usr/portage/x11-plugins 605K /usr/portage/x11-proto 765K /usr/portage/x11-terms 2.6M /usr/portage/x11-themes 1.5M /usr/portage/x11-wm 26M total
The work involved out weighs any potential benefit