Interesting. The only time I used a scroll saw on a pen was to scroll bats into a pen I did for a Halloween contest. I have seen pens that have wavy lines in the blank with contrasting wood. It looks very nice. There is also cast blanks that has scroll sawed objects cast, like leaves, that makes beautiful pen. I think I saw a tutorial on this in one of the two scroll saw mags I've bought.
This is the pen I made for the contest. It is out of black PVC pipe (pieces glued together), the bats scrolled into it and filled with paint mixed in epoxy.... I won the contest. There were only about 8 participants...