Just a note for Chris on the slitter and chopper. Much of the RIT equipment was made at EK and used there originally.
Also, the slitters and perfers became dull with use and had to be replaced on a regular basis. Kodak used rotating dies for all of this. As Chris said, this is all very simple in theory!
Now, as for backing paper and etc, yes, paper is available and yes, 120 is a good target, but grain and sharpness are what might bite us even in 120 size, and so this is why I am targeting 4x5 and larger on film or plate. I have quite a few glass plate holders and hope to coat them and some film for use in my 4x5 camera.
BTW, Mark and I will be teaching a workshop on Bromoiodide emulsions in March 2013.