Whatever service you don't need and which is also not needed by JBoss internally you can take them out, especially the MBeans from JBossMQ.

Note that later JCA will be used to deliver JMS messages to a message driven bean which means that you can't get ride of JCA when you are using MDBs.
Another example is Hypersonic when the JDBC2 Persistence Manager is used in JBossMQ (you can't remove Hypersonic).

Have fun - Andy