I think you will have trouble with RMI code mobility. I certainly did when trying to make MBean services JINI aware.
I couldn't get the JBoss class server to work - it looks broken to me on a very cursory examination. Without this (custom classloader annotations) you are stuck with setting the RMI codebase in one place for the whole JBoss JVM. You could ship a WAR with the reggie-dl.jar in, and set the codebase using the system property when starting up JBoss to point to the jar's URL.
However, you can't add any other services that allow clients to download code - because they would all have the codebase URL of the reggie component.
You could create a shared classloader WAR - but you would have to modify it each time you added a new JINI service... not really a solution.