Is there a solid way of using either X directly or KDM/GDM/KDE/Gnome to quickly switch between an external screen and modify the screen layout accordingly? I'm stealing the inspiration from Windows 7's +P functionality, where a central popup shows 4 different possible layouts: only external, duplicate, only internal screen, extend desktop.
I can switch between any (or at least most) of these by using the Nvidia control panel (and if I was using the open source drivers, through the KDE X screen configuration option screen, and something similar for Gnome). I would like a faster way to just switch output, without having to go through billions of menus (ok, slightly exaggerated, but still... you get the point)