you also could invert the constrain inward , but outward is best.
combinations of horizontal and vertical polychain is also possible for greater effects.
i'm sure the community will find derived version of this technic.
all you need now is to model your cloth with it's folds and take
every segment (paralel or vertical) and make them Polychains.
you'll get a nice secondary motion that SBD gives.
hmm ...how should i call it... Polychain SBD??
i like it ...C&C are welcomed.
Samus