Here is my take:
Use mdm + onboard + window manager.
Not sure about the security consequences (more processes running, onboard run macros, etc), but it worked for me.
I especially like the ability to move and resize the keyboard. I use it with my portable mint on usb, on my eeepc with broken keyboard and on a desktop which I dont trust the real keyboard (dont ask
sudo apt-get install onboard xfwm4
--- My " /etc/mdm/Init/Default " (at end of file):
onboard -x 30 -y 30 &
LOL , yesterday I could not find the keyboard when logging in. Turns out I Was using my eeepc, with a smaller monitor resolution.
The virtual keyboard was too far below to be seem. So keep onboard close to login screen or use: onboard -x30 -y30 , for instance.
Also note that onboard can be in minimized mode or even transparent! Check the docs.
---- My /etc/mdm/PostLogin/Default
#Seems important: exit 0 . Dont init session if previous command fail.