[sclug] Display graphical desktop session of remote machine?

[John Stumbles]

Not sure how to even explain what I'm after succinctly.

I have SuSE with KDE running on this machine, and ubuntu with gnome on 
my other box. On this machine I can 'switch user' and run another 
completely separate graphical session on a different vty (switching 
between sessions with Ctrl-Alt-F7 and Ctrl-Alt-F8 etc). These extra 
sessions run on the local box but I'd like to be able to run a session 
from the other box displayed on this one, i.e. use one graphical session 
on this machine as an X server for a display manager and apps on the 
ubuntu machine.

Alternatively it might be OK (maybe even better) if I could run a gdm 
session from the other machine within a window on my kde session on this 
one (as I have done in the past with some X servers or a VNC client 
running on a windoze box connected to *n*x machines).

 From a term within my kde session (or from a tty if I set DISPLAY 
appropriately) I can do `ssh -X user at ubuntubox xterm` and get an xterm 
up on my existing kde session.

However if I try to run gdm or startx instead of xterm I get errors 
telling me I'm not authorised to run them as myself, and another variety 
of errors if I try to sudo the commands.

I suspect it's quite simple When You Know How (tm). Anybody know the 
secrets?

-- 
John Stumbles