Maybe I don't understand the problem, but non-web resources can be retrieved from the file system via regular Java IO. See FileInputStream.
Then I think you need to do a new File(....). getResourceAsStream() is only for loading stuff from the classpath.
In addition to what's been pointed out already:
1) To solve the re-deploy problem, you can always deploy in exploded (directory) form. Then you'd always be able to add/change files freely. This only works if the files are inside of your myapp.ear/whatever.war directory, but it does solve your redeploy problem
2) If you want to really externalize this, you might also look at the ExternalContext MBean. (section 3.5.3 of the JBoss AS Guide) You can bind any just about any file system like structure (local or remote) into JNDI and access the resources that way. It's a bit heavy of a solution, but it is very flexible.