Launching/Switching to another colour depth from gdm screen

[db <bosto tpg com au>]

Hello gdm people,
	I have a situation where a few old but frequently used programs will 
only work on 8 bit displays.  I can get gdm to bring up two instances of 
X with different colour depths, but it's still confusing for people to 
switch to another linux virtual terminal by keys and log in again.
	What I would like to be able to do is have the user choose an 8 bit or 
24 bit display from icons at login and have the virtual terminal switch 
or X restart in the other colour depth (like xdmphoto+xdmopt is supposed 
to do).
	A better option that would achieve the same goal is to have the user 
log in once, spawn two copies of X at different depths, and initially 
display the one with the highest colour depth.  Sadly, something as 
simple as Xnest or Xvnc is not the answer - it needs to be a real 8 bit 
server and to convince appliations of the fact.

Anyone have any ideas on how to do either of these things with gdm?

Regards,
	David Boston