I do not have an ETA for this. I would imagine several releases before this is ready. The Mass plugins will likely be worked in the order of MassGameplay->MassAI->MassCrowd.
ZoneGraph has not seen much development outside of some bug fixes since 5.0. I do not know when it will be production ready as efforts have largely been focused on other areas. I imagine it will start to see more development once we have moved onto the MassAI plugin as that is the primary user of ZoneGraph currently.