One answer to this scenario is to use a pre-calculated digital buffer that will output say a 500mS worth of data whch gives you your 100uS clock. Then output this as a pattern and keep the buffer topped up and circulating (servicing the buffer at >1mS periods). If you are just using the parrallel port or something then this obviously doesnt work but I am assuming you have a DIO module in your USB chassis. So I can see why a sub mS tick count would reduce your hardware in this scenario but id rather get the 100uS clock correct and not have to bother with additional coupling and smoothing out mechanical jitter etc
Interesting topic although im not yet convinced 🙂
Saying that I am only sceptical because I cannot think of a use case. Not a bad Idea and would be nice to have in the event that the need for sub mS timing does arise.