The picture was mostly to illustrate how you could mount separate pulleys on the same shaft to get your gear reduction. And there are ways to create more or less that motion system/gantry with square rods. I don't recommend it for cost's sake, since it needs 6 rails as opposed to 3 for an H type gantry. Also, drivers are rated to '2A', but I wouldn't recommend running them that hot, especially the plug in types. Most people run them under spec as a bit of a safety margin and to avoid overheating issues.
Wire cutter with a servo? Simplest idea me thinks is a razor blade from a box cutter, have it in a slot across the feeder tube for your wire, and have your servo pull it though the slot to cut the wire. I wouldn't recommend scissors, go with something replaceable (ala razor blades) since a blade cutting a wire in the exact same spot, over and over is going to get dull quickly.
