for example: how much disk space is /var/db/pkg/net-www/lynx-2.8.4a-r2 consuming? (no, not the ebuild file! all the installed files from that package ;) i dont know where this thing "fits" ie: portage, gentoolkit, etc. but i think it'd be a nice touch.
Added as pkg-size in app-admin/gentoolkit-0.1.7