Some time after a world update I noticed that XFCE's desktop settings no longer listed SVG wallpapers from x11-themes/larry-backgrounds. Also, the XFCE menu was lacking icons for Blender 2.5x. sudo revdep-rebuild didn't seem to help. Some digging in the code of xfdesktop quickly revealed that the loader of gdk-pixbuf didn't like loading SVGs anymore. For some reason re-emerging x11-libs/gdk-pixbuf solved the issue. Processes that needed killing and a re-launch were xfce4-panel and xfdesktop for me.