Generally I make an ejb-client.jar which as you mentioned has the remote and home interfaces so it can call the server.
As for the jboss client jars, it will always depend on what you use. You don't need all the jars in there, best to just add them as you need them (ie they show up in an exception). If you use jboss specific stuff then you will have a problem,otherwise you should be pretty portable.
Another option might be java webstart so you can keep all your jars and such centrally and keep clients updated.