In the Ubuntu Developers Summit, Aurelien Gateau presented a project that he has been working on for the next Kubuntu release i.e. Kubuntu 10.10 Maverick Meerkat. He introduced a Global Menu for KDE SC following the announcement of Global Menu for GNOME that Mark Shuttleworth made earlier. However, the feature is being developed for KDE SC 3.x and has not been ported to KDE SC 4.x yet.
The Global Menu implementation uses D-Bus, which means that GTK+ applications running in KDE will also have its menu bar in the Global Menu. As Shuttleworth pointed out when he introduced the Global Menu earlier, this is mainly aimed at Netbook users to maximize the vertical pixel usage at the expense of horizontal space.
Here is a video to demonstrate the Global Menu: