Gnome 2.12 introduces support for selecting xcursors themes (gnome-mouse-properties). Gentoo xcursor themes are installed in /usr/share/cursors/xorg-x11 which is unfortunately not a path searched by gnome-mouse-properties. The following patch adds path to the list of directorys searched. We already apply a patch to libXcursor (and monolithic xorg-x11) to add this path there too.
Created attachment 66821 [details, diff] path to add neccessary paths
Thanks for the patch Herbie. Applied in control-center-2.11.92.ebuild.