The floor space occupied by some of these beasts would hold half a dozen of today's racks.

That doesn't include the footprint of some of the supporting equipment you mentioned. The bit about six-part forms reminded me of my old decollator. Equipped with four catch bins and three take-up rollers for the carbons, it would separate all copies of four-part paper in a single pass. At operating speed it could paper cut a country ham. The first time my wife saw it in operation, she commented "I'm not coming anywhere near that naked."