I could envision using a sliding back tethered to live view and measure focus peak a la Capture One, but for sheet or roll film it would require a sliding adapter that I have never seen. On my Sinar, even the ground glass graflock back is slightly off the plane that my digital slider has. I use ground glass to compose if I am stitching and the camera always needs slight refocus when I attach it and attach the digital back.
For the OPs example of a View camera against the ceiling, I've never been in a setup that I couldn't get behind the camera or use an optical reflex viewer, but for a thought exercise on how I *could* manage that shot without a focus aid....set up would be a ton of measuring (Distance from film plane back to subjec)t, , set up a target and camera to the same distances, focus, and set an exposure with as small an aperture as needed for depth of field to cover the subject (would assume it's shallow anyway given the angle described. Move camera into position and somehow compose the shot....and mutter under my breath the whole time about how much easier this would be if the Art Director wasn't insisting on film so I could just shoot digitally and use live view so he could sit on his butt and look at the proofs on his iPad, but hey, it's his money. No way in hell I would do a set up like that without someone paying me to do it!
