Sure thing. What you're looking for is called Xnest. It's both an X server and a client that can run and display in your current X/GUI session. I believe it accepts some of the standard X command-line arguments, i.e. -geometry, -depth, -query, :N (where N is the display number you want it to use).
The package/version of this that i've got installed is xorg-x11-server-Xnest-1.0.1-9.fc5.5, which is available at
http://download.fedora.redhat.com/pub/fedora/linux/core/5/i386
/os/Fedora/RPMS/xorg-x11-server-Xnest-1.0.1-8.i386.rpm for fc5 and at
http://download.fedora.redhat.com/pub/fedora/linux/core/6/i386/os/Fedora/RPM... for fc6.
You can use your favorite package manager GUI, or from a command-line: yum -y xorg-x11-server-Xnest -or- rpm -ihv url_to_packagename.rpm
Note that it is not in the extras repository; it is one of the core packages.
You sound like you know what you're doing, anyway; the man pages are pretty helpful.
Hope this helps. Holler if ???s.
- gabriel
Thanks. This worked great
Xnest -geometry 1024x768 mynode :5
Bob Styma