The RichFaces team has just released 4.0.0.Milestone6, and we are well on our way to RichFaces 4.0.0.CR1!!
For more information see Jay Balunas blog entry at in.relation.to. Check also the Release Notes which contains all the details, and specific issues.
You can download the artifacts from the download page or if you are using maven, you can update your dependencies following the How to add RichFaces 4.X to Maven Based Project wiki page.