I think it already IS ported. From the Rhythmbox developers' page (http://projects.gnome.org/rhythmbox/developers.html) under the building from source:
GNOME 3.0 or newer (including GLib 2.28 and GTK+ 3.2) -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to rhythmbox in Ubuntu. https://bugs.launchpad.net/bugs/977493 Title: Interface need to be ported ti GTK3+ To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/rhythmbox/+bug/977493/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs