with USE="fallback", gnome-base/gnome-3.8.0 depends on gnome-applets as well as gnome-core-apps. However, gnome-core-apps block gnome-applets. That doesn't seem to workout.
+ 02 Oct 2013; Pacho Ramos <email@example.com> gnome-3.8.0.ebuild:
+ Waiting for a newer release ready to be used with gnome-panel-3.8 and 3.8
+ ecosystem (#486750 by Sven)