Just had a thought.  If you were to export a number of the cloth variations and re-import them as morph targets into the original cloth - or a neutral version of the thing - then you could apply the morphs to go along with the figure's pose.  Those COULD be saved to the pose library along with the figure.  A prop's relationship to the figure its parented to IS saved the pose library.  Any morphs, by default, would be saved as well.

Best Wishes,
R-