GStreamer 1.0 will be coming at the same time as GNOME 3.6, and a number
of applications are getting ported to it as we speak.
See https://live.gnome.org/GnomeGoals/PortToGstreamer1 for a list of
GNOME applications that rely on GStreamer, and their port status.
We would need enthusiastic packagers to create the first versions of the
parallel-installable GStreamer 1.0 package. This means 1.0 packages for:
Anyone want to get that started?
There has been discussion on the Xfce list about the Bridge GTK2/3
theme  which is a port of Adwaita. From the description on
GNOME-Look "This theme is a 'bridge' to bring GTK 2 and Qt
applications along on your journey to enjoying GNOME 3 with Adwaita.
Pixmap engine required."
Christoph informed me that perhaps there had been some discussion
already of taking this theme and packaging it, so he suggested I asked
here first before doing anything.
If there are already no plans in place, I was thinking of packaging
this up for Fedora.