While we wait for the Mesh Deformer people are looking for ways to make mesh clothes fit. There are some alternate methods for making clothes that change with the avatar shape. One of those is the use of Collision Bones. Some call it Collision Volumes. We have heard that method called liquid mesh in promotional stuff. It works to a point. But, how does one use Collision Volumes?
Using the Collision Bones in the default SL avatar one can achieve some measure of sizing tied to the avatar shape. The problem is getting that information from the modeling program to Second Life™.