I have also been trying to tone down the logging level without success.
I have modified the /usr/local/jboss/server/default/conf/log4j.xml to use ERROR and INFO levels, but the server.log is still filled with DEBUG information.
I do not see any changes on the LINUX server; however, it works fine on Windows XP using the exact same jboss directory. That implies a dependency on an envirnoment variable or classpath.
I have also modified the tomcat/conf levels without success. I am using JBOSSS 4.04 with JBP Beta1.