After the fix to http://jira.jboss.com/jira/browse/JBAS-4355, the JBoss trunk now creates a MANIFEST only jbossall-client.jar with references to other jar files. The readme in that jar mentions this:
This jar file contains a classpath reference to various client jar files used by jboss client applications.
Each of the jar files in the following list must available in the same directory as the jbossall-client.jar, Otherwise they will not be found by the classloader.