Portage is becomming a mess, all themes, cursors, icons, etc.. should be moved to a new directory eye-candy with a simple naming convention [application][type][name] application = application which the package belongs to type = type of the package - theme, icons, etc... name = actual name of the theme/iconpack/etc... Example: kdm-theme-TuxMania, x11-cursors-comix,...
Please, go suggest this to gentoo-dev mailing list, bugzilla is nor a proper place for such requests. I personally don't see much advantange in shuffling this stuff around. http://www.gentoo.org/main/en/lists.xml
