REALLY WOULD LIKE NIKON TO SUPPLY A SPLIT-IMAGE FOCUS SCREEN FOR D800 et al.

I agree. Since switching to auto-focus, I have had more out of focus or slightly soft images than ever before. With people photography and manual focus, I might have had one or two slightly soft images per 100 shots but now, with auto-focus one assumes the camera will do the settings for you but you are never sure of your exact point of focus especially when working quickly. Auto-focus has its place but I would like the manual RFR option included as well.