I would like to be able to do xhost +localhost so that I can run X-based programs after doing an su to root. I have set DISPLAYMANAGER_XSERVER_TCP_PORT_6000_OPEN="yes" in /etc/sysconfig/displaymanager, but the X server insists upon starting up with -nolisten tcp, as shown by this line from ps aux

root 3251 9.9 5.7 42172 21188 ? S 09:38 5:00 /usr/X11R6/bin/X -nolisten tcp -br vt7 -auth /var/lib/xdm/authdir/authfiles/A:0-qJklEc

/etc/sysconfig/displaymanager recommends instead using SSH with port forwarding, but I'm not sure how to do that. (I cannot do "ssh 127.0.0.1" as root; I get ssh: connect to host 127.0.0.1 port 22: Connection refused)

Any solution would be greatly appreciated.

as far as the -nolisten-tcp option, i have mine enabled in the file " /etc/X11R6/bin/startx "
for ssh you must enable sshd, try " service sshd start"
the config for that is in /etc/ssh/sshd_config , i think.
also make sure that your firewall opens port 22.

hope this helps