Nightly build that contains the fix http://community.jboss.org/thread/167590 for the "DeploymentUnitProcessingException: only one persistence provider can be packaged" exception.
Are you planning on switching to use Hibernate as the persistence provider? If no, please describe why not (I'm interested in answers to this question from anyone).
You are not the only one that wants to use EclipseLink but that is not ready yet. If anyone wants to join in the community effort, to finish the EclipseLink integration. Please express your interest.