Thinking about a CNC router with x, y, and z axes controlled exclusively with steel cables under high tension. The main gantry travel would be rigged similar to the parallel on an old school drafting table. This would eliminate racking.
The transverse and z axis travels would be two pulley simple arrangements. The drive pulleys would be mounted to ball bearing pillow blocks and coupled to either planetary reduction stepper motors or Gilmer belt reduction sprockets to steppers.
In elevators and cranes steel cable has been well employed in traction applications. By selecting proper pulleys and holding adequate tension there is no good reason why tensioned cables could not save money and replace ball screws, racks, and long Gilmer belts as CNC drives.