User switching in Xfce4

Just install gdb3 and xfswitch-plugin (this is for debian wheezy):

apt-get install gdb3 xfswitch-plugin

The plugin can the be added to the Xfce4 panel.

gdb3 can be configured in /etc/gdm3/greeter.gsettings for background color or images, and in /etc/gdm3/daemon.conf for autologin of a given user.