When I think of modeling in Carrara, the person that comes to mind is litst. I don't know about clothing but you might try this tutorial (about head modeling)- of course head modeling is quite different from what you asked about but there may be something in it you can use to manipulate vertices/faces the way you want to. http://www.chez.com/litst/eng/tut-head2/tut-head00.htm