I'd presume I'd have to do 3 things to make this a practical reality:
1) Transform the second instance over about 65 mm (eye separation).
2) In the vertex shader, render things based on instance ID on the left & right side of the screen.
3) Automate creation of the second instance for objects added to the root node
The slides talk about how to go about clipping with "SV_ClipDistance and SV_CullDistance", never used it, though.
I'd be able to determine which side is being rendered by the instance ID we've been talking about above.
Quite the undertaking, though. UE4 & Unity even acknowledge the work involved. Very interesting, though. I currently skip shadows altogether, but implementing this might allow shadows in.