Here is a link to the B&H article with more detail. The Vello autofocus adapter for Nikon to Sony E mount is coming soon! Looks like it's dropping in May 2016.
After long wait, and selling almost all my Nikon lenses, we'll have an adapter soon that provides auto focus! I'm sort of excited, a little upset, but mostly excited. I sold all lenses but my Tamron 70-200 2.8 which I love. I still use it manually at times, but a couple lenses I would have kept if they could have auto focus.
This new adapter has a promise of bringing to life many lenses for folks that have made the swap to Sony E mount but have not yet sold off the old Nikon gear.
Selling for $399, I'll be looking at some reviews from the testers on whether specifically the a7r2 can handle the autofocus with speed like the Metabones adapters do for Canon lenses.
Look for more updates as I see testing come in.