Can two publisher reside in CCM 6.0 Cluster or subscriber can be promoted to be a publisher in CCM 6.0 Cluster.
CCM 6.0 has the same design considerations as before when it comes to the Single Publisher with multiple Subscriber setup. My understanding is that Cisco is working on a method to promote a Sub to Pub for Disaster recovery purposes, but this has not yet been released. Soon I hope :)
Hope this helps!