There were suggestions from Autodessys a LONG time ago that a Vray plugin was in the works. I think this is one reason it is fair to ask how it is coming along. For my work speed is critical and Vray is an attractive option in that regard.
Not suggesting for a second that the question isn't worth asking with regards to what Autodessys can tell us.
Otherwise anything we discuss here is nothing more than conjecture.
It interests me that Autodessys have yet to comment in this thread. And seeing as we're in the realms of conjecture this means:
a.) They are awaiting to announce something positive with regards to third party rendering plugin availability (subject to finalising current conversations).
b.) The have nothing to add to the conversation because there are no ongoing discussions with regard to any new third party rendering solutions.