The T-shirts from my last hobby are getting ratty. Couple of searches for Mach shirts turned up nothing.
Has nobody ever made up any Mach T-shirts? If not, it seems like easy money for the good folks at ArtSoft. A logo with some kind of catchy statement would be easy for those artsy folks that do T-shirts in bulk. Something like "Control the world of CNC with Mach 3" or whatever. Then when Mach 4 catches on you have another opportunity.