I am looking for some too Brian.
But I won't be making them. Many are like a smooth spacer to follow the original line and one or two more little 3/8" long sections of triangular needle file to cut the subsequent grooves.
I am up for making a lot of kinds of tools, but that is a bit much. :)
I have done it by hand a number of times with an ordinary bent riffler though. Can't quite get it as even.
yours Scott