RFC local modify of gnome-screensaver unlock and or pam

[Skunk Worx]

Goal:
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When using gnome-screensaver I would like a simple unlock dialog that 
prompts for both user name and password. It should not show the current 
user name. If the (user,password) pair authenticates, the current user 
desktop is unlocked and the applications are again visible. The unlock 
(user,password) pair need not be the owner of the desktop.

Background:
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I am creating an information kiosk.

On power-up it does an auto-login and locks the screen with 
gnome-screensaver-command. Finally it auto-starts a number of graphical 
system status applications.

There exists a set of (user,password) pairs that should be able to 
unlock the screen and see the currently running applications.

After one user authenticates with their (user,password) pair, the user 
locks the screen with either the menu lock option or the screen will 
eventually lock due to a screensaver timeout.

Another user can then walk up to the kiosk, unlock the screen with their 
specific (user,password) pair, check the system status, and then leave. 
This should be logged so I know which user is looking at the system 
status apps at any given time.

The process continues with other (user,password) pairs as necessary.

We don't want the users to have a single (user,password) pair.

Current Status :
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It looks like Fedora 7 will be the basic platform. I am using FC6 for now.

Auto-login, starting the apps, locking and unlocking the screen with the 
   auto-start system (user,password) are all working.

However the dialog that pops up to unlock the screen shows the 
auto-login user name and prompts for a password.

So far I have tried adding "user1" and "user2" using the -o option to 
useradd (giving them the same UID/GID as the auto-start account) and 
then setting "user_switch_enabled" for gnome-screensaver.

Unfortunately this is not enough:

1) Actually switching users only shows "other UID" users in the 
selection list, not the "sibling UID users".

2) Switching to a "other UID" user creates a new Desktop for the other 
UID, which is as expected, but not desired. Useful for testing though.

3) Switching users again from an "other UID" shows all the "sibling UID" 
accounts in the list. Selecting one of the "sibling UID" users (but not 
the auto-login user) gets to the auto-login desktop configuration, but 
without the auto-started applications visible.

It appears I will have to modify the gnome-screensaver-dialog and 
possibly pam to get this to work.

I have looked at the g-s src rpm plugin code and have considered a few 
mods but haven't tried anything yet.

Before continuing I thought I would ask here for advice, comments or 
suggestions.

Thanks,
John