I have jbossas/ejb3 just producing the ejb3.deployer using just the org/jboss/ejb3/deployers/** classes.
The current jbossas projects using jboss-ejb3-core are:
ejb3 - deployers
embedded - org.jboss.ejb3.tx.TxUtil
testsuite - org.jboss.ejb3.client.ClientLauncher
tomcat - numerous inject related classes, org.jboss.ejb3.enc.DeploymentEjbResolver
webservices - org.jboss.ejb3.BeanContext, org.jboss.ejb3.stateless.StatelessContainer, org.jboss.ejb3.Ejb3Deployment, etc.
I'm working on the injection/resource resolution logic which will fix the tomcat dependencies. The webservices dependencies are the ones needing to be resolved with the ejb3/ws spi work.