It would be great if the packaging of Hibernate could be done as osgi compatible jar. With little configuration, some plugins already exist to do it in simply.
For informaiton, a jar can become osgi-compatible only by adding some properties inside the META-INF/MANIFEST.MF file. It lets the jar totally usable in a non-osgi environment, but let the jar be recognized as a "bundle" in an osgi-container (Eclipse, Apache Felix...).
A good entrypoint for this, using maven2 to package, could be http://felix.apache.org/site/maven-bundle-plugin-bnd.html#MavenBundlePlugin(BND)-AddingOSGimetadatatoexistingprojectswithoutchangingthepackagingtype.
For example, Spring already did and their available jars on repo1.maven.org can be put directly in a eclipse/plugins directory and be recognized as a bundle/plugin.