Actually I don't think the pull requests have been accepted. If you want to try it out I think my Github repo is the best source. I'm using successfully!
I start a project with hibernate 4 and if i understand this thread. They are not yet hibernate-tools for hib4 to do reverse engineering, isn't it?
Under maven repo hibernate-tools 4 CR appear http://mvnrepository.com/artifact/org.hibernate/hibernate-tools.
Does this release support reverse engineering ?
there are hibernate tools core, ant and eclipse versions that supports hibernate 3 and 4.
The only known issue at the moment is you can't use hibernate 4.3 to run the generation, but you can use the generated output (using hibernate 4.0,4.1 or 4.2) with Hibernate 4.3.