I've created this to serve as reference for those looking for it. Ebuilds are developed in kde overlay (as two other KDE4 ebuilds use system-config-printer-common) here: http://git.overlays.gentoo.org/gitweb/?p=proj/kde.git;a=tree;f=app-admin/system-config-printer-gnome; I'll handle tree inclusion myself when I feel it's ready, so please don't move it on your own yet.
Version 1.1.16 in kde overlay. CC-ing GNOME herd, maybe you'll be interested in picking it up. Good thing is - it's actively developed, supports polkit-1 (and polkit-pre-1 as well - controlled by configure switch - I've forced it to polkit-1 in system-config-printer-common). Bad thing is - splitting this package off from system-config-printer is a bit tricky (buildsystem provides no clear indication what's common and what's gtk-specific - maybe upstream could do sth about it).
Now in portage, don't cry when it breaks :P
