'dev-qt/qtgui:4[dbus(+)]' is wrong, latest qtgui ebuild does not have qtdbus dep now, see https://bugs.gentoo.org/show_bug.cgi?id=478222#c4
+ 08 Sep 2013; Agostino Sarubbo <ago@gentoo.org> marble-4.10.5.ebuild, + marble-4.11.1.ebuild: + Fix missing DEPEND of qtdbus, thanks to Nikoli, wrt to bug #484172