I used Hoodman LCD caps on my Nikon D1x, D2Xs and D3 cameras. The optical quality was adequate rather than excellent, but if the back of the camera received a blow I thought that the Hoodman would absorb some of the impact, and not cause damage to the LCD screen with glass shards.
On April 27, I emailed Hoodman to ask about the availability of a hoodcap for my then-new Nikon D4. On May 1, I was informed that “Our H-CAPD4 will be available at the end of this summer.”
I checked in again on August 7th, and then was told: "The D4 Hoodcap is running behind schedule. It will be another 6-8 weeks." I waited until Nov 2 to ask again, but received no reply to that inquiry.
I wrote in again tonight, and will advise if I learn anything.