No, I like challenges :-). Now, there is one thing. What is the remote X program that you are attempting to start up. Several times I have seen programs that, internally as part of their startup, reset the DISPLAY environment (assume that it isn't set, reset to localhost:0 kind of thing). Start with the most basic, try to remote display an xterm. That is my 'basic test' when I remote display.
You can always
tail -f /var/log/messages
to see if there are errors when the remote session attempts to connect.
Keep me posted.