I can't tell you how to stop it from loading - there may be some section to comment out in /opt/kde3/bin/kdeinit.
I can tell you how to kill it after it has started. Open a Konsole, su to root, run top. You'll see several instances of kdeinit running. The trick is to figue which one represents the panel. To do this, manipulate the panel in some way and watch which kdeint shoots to the top of the top outout. Get the PID, then kill the process.
Actually, a better way is too run "ps aux" and look for the PID for kdeint: kicker. Then kill the process. If you need to start it again, run -> kicker.
Sorry, not thinking clearly before