"Switch User" type of desktop setup?

[Mark Knecht]

Hi,
   It's been on my mind lately to try and come up with something that
would allow all members of the family to use the same computer more or
less at the same time. Windows has a 'Switch User' concept where you
can walk up to a locked machine and, if you have an appropriate
account, you can switch to your account while leaving the other
person's account logged in and running. (Well, sort of but this isn't
about the limitations of Win XP...)

   Maybe this is all built into Gnome alredy and I haven't found it.
If it is please point me in the right direction.

   Anyway, I have managed to show people how to shell to a console,
log in, and do a command like 'startx -- :2' but that only works for
non-Linux types if no one is using the display they think they are
supposed to use. (I.e. - they really don't know about display numbers
:0, :1, :2, etc. and they tend to repeat each others display
numbers...)

   What would be really great in my mind would be something like the following:

1) You come up to a locked or unlocked machine and hit Alt-Ctrl-Del,
or some other preset set of keystrokes and you get the normal gdm
login screen

2) You log in as normal. If it's a new login then gdm/X/something else
figures out an open display number to give you and your desktop shows
up as normal.

3) If it's an existing login then you are taken to the display that
you already have. As an alternative you can search with Alt-F7/8/9 and
try your password on each screen until you find yours.

4) As a security bonus when you log on this process would ensure that
other user's screens become password protected f they have set
password protection on xscreensaver.

   Thanks in advance for any ideas and pointers on how to make this
desktop more multi-user friendly.

Cheers,
Mark