There is no reason that dual motors can't be used with ACME or ball lead screws to help prevent racking of the gantry. It doesn't provide much of an advantage versus cost for small machines. By the time the machine size becomes a problem with racking people now tend to go to rack and pinion drives anyway. A few years ago that was not really much of an option unless you designed and built your on drives.
60" with ball screws is at the point where you need to consider rack and pinion drives. You will be limited in jog speed by lead screw whipping. Rack and pinion doesn't have that potential and 1,000+ inches per minute jogs are possible, although it's not very useful.
Racks and ACME rods are not always exactly the same either, but adjustments can compensate for most differences.