It should be possible, are you seeing any specific issues?
I'm having trouble with the library dependencies. What I'm doing trying to do is very straightforward. Create a seam project (Seam 2.2.1 CR2) with seam-gen. After the project is created I remove the Richfaces libraries in the Seam project (Richfaces 3.3.3) and add the Richfaces 4 M4 libraries. I also update the deployed wars and ears description files to include the new richfaces libraries. Then I have tried to deploy the project to both JBoss AS 5.1 and JBoss 6 M5 without success.
My question is if there is anyone who can describe how to setup a Seam 2.2.1.CR2 project with Richfaces 4 M4 and deploy it to JBoss AS 5.1 or JBoss 6 M5 or later.
We don't have any examples of this atm. If you share what errors you are seeing, we might be able to walk through this with you.
Is the project building? Have you changed any of the RichFaces tags in the xhtml files? What is the deployment errors?