This forums is specifically for design and other related questions for the new JBoss Messaging system which your question is not.
You should repost your question to the user forums for JBossMQ which is the old JMS implementation using uses the innovation layers you are referring to. Also I would take a look at the JBossMQ wiki (http://wiki.jboss.org/wiki/Wiki.jsp?page=JBossMQ) as it contains a stack of information around configuring JBossMQ to achieve greater performance. As a start look at using the UIL2 invocation layer as the OIL and RMI have been deprecated.
Have said that if you are looking for higher performance and only currently require a single server (as in no clustering requirements) you should seriously consider using JBoss Messaging rather than JBossMQ (default JMS solution with JBoss AS 4.0.5) check-out:
If you have any specific questions of JBoss Messaging post them to the JBoss Messaging Users forum (http://www.jboss.com/index.html?module=bb&op=viewforum&f=238)