I've seen a few torch holder/actuators and a perhaps a few more spindel Z-axis units on this website. Stored all the interesting ones in my files, but not necessarily by that feature, just the guys name. Too many to go through!
Anybody remember the member names with good Z mechanisms suitable for a plasma torch or a light drill? The search feature on this site doesn't seem to return what you're looking for.
Are there any premade units? I recall one in the woodworking forums from a few years ago. That would have been geared for drilling or light routing. I would make or buy a different head for each purpose.