NVIDIA has begun their own independent Beta for mental ray 3.14 for Autodesk Maya 2016.
Its nickname is “pi-ray” because, you know, 3.14159….
This is a development alpha/beta. Features are introduced one after another for testing and feedback instead of one big bag of features all at once.
Take a peek at their forum post for requirements and then send them an email to sign up! (You have to be a forum member to participate.)