The Gnome Flashback team has released Gnome Panel 3.8.0, a wrapper script for the good old Gnome Session Fallback. It is based on metacity and gnome-panel, and offers a similar experience to Gnome Classic.
The Gnome Flashback team has started work in December 2012 and invited many third party developers to join their team, including the MATE developers, which have created a famous Gnome 2 fork called “Mate Desktop”, in order to provide a Gnome Classic experience to the Gnome Desktop.
Despite the fact that there are some integration issues with the Gnome desktop, Gnome Panel 3.8 is a mature flavour of the classical Gnome-Panel.
In the default repositories, Gnome Panel 3.6 is the latest Gnome Panel version available, but Gnome 3.8 should be added soon. Until now, you can download the gnome-panel-3.8*.xz archive and try to install it from sources. For more information, see the official mailing lists and the changelog.