Logout using DCOP calls
Here's what I've dug up.
Dan Brough in kde-kiosk
Default way of doing things:
dcop kdesktop KDesktopIface logout
But to get rid of annoying dialog:
dcop ksmserver ksmserver logout 0 0 0
will log the user out, overriding the confirm dialog, also:
dcop ksmserver ksmserver logout 0 1 1
will reboot the machine.