Starting situation: we have some EJB's using Apache Cayenne and want to provide some web services or RESTful services hosted on an application server. Geronimo, Jonas et al are all quite complex and a more simpler server would benefit for small applications or development environments.
Approach: having used already OpenEJB with Apache Cayenne brought our attention to the new Apache TomEE. As we wanted to use as well Apache CXF in order to provide JAX-WS/RS services the usage of Apache TomEE Plus caused quite some issues with CXF. TomEE Plus has bundled CXF however using CXF from its original distribution is more desired. So switching back to the "Web Profile" and the using CXF out of the box brought the desired environment. Deploying of a war containing the EJB jar and all the rest had the right effect. EJB's were available like you would deploy them through an EAR directly to OpenEJB and the access was available as http://127.0.0.1:8080/openejb/ejb.
All in all this seams to be the right setup and runs easily on Unix and Windows. As of writing Apache TomEE was just released as 1.0 Beta 2. See yafra wiki for more information on setup and development.