Ah, I understand what you are trying to do.
I have done this (multiple X sessions on each tty) by doing what is in this link.
But this was only on the local machine.
As far as making each tty on the client run an X session from a seperate host - I have not tried this, however this link may be of additional help.
You'll have to issue a command on the server allowing X to be exported to the client. I have done this from within a local X session (i.e. graphical display of YaST2 on my client using the server's X). Generally though I use the command line and ncurses display in a terminal to admin my server.
Knoppix - rarely use it - has some application in KDE that configures and performs this function I think, but I forgot the name - I fire it up later and see what it is. I never got so far as to configure it.
This looks like an intresting thing to play with. What were you doing/using in KDE to accomplish this?