Hibernate Core 4.0.0.Beta4 has just been released. The complete list of changes can be found in JIRA release notes
Most of the work is still occurring in relation to the new metamodel. A primary milestone in this release is the consolidation of how bindings get built between annotation processing and hbm.xml processing (see HHH-6447 for details). And Gail has started getting the metadata integrated into the Hibernate
engine! So all in all things are really moving along.
The release is available from SourceForge in bundle form as well as from the JBoss Nexus repository (now synchronized to Maven Central!) under the org.hibernate groupId.