Lee, I've seen a few dresses or skirts that have them.  If you are lucky there might be bones to control the skirt... those seem to be a little more common.  I don't think we see more because you'd actually have to create a morph yourself.  Make a mirror of it if it's a L/R morph, etc.

WARK!

Thus Spoketh Winterclaw: a blog about a Winterclaw who speaks from time to time.

 

(using Poser Pro 2014 SR3, on 64 bit Win 7, poser units are inches.)