Yes, it can. However it is dependent on the JBoss AS, as it uses mbean services. Also, you would need to write a custom permissions service (which reads user and role information - this is of course portal-specific).
Deploying it as a servlet requires:
* changing ViewHandler in faces-config.xml
* changing services in jboss-service.xml to read from servlet init-params not from portlet preferences
And I suppose that's it :)
What need to be done to deploy in jboss-portal 2.4.1