Attached Link: http://www.rbtwhiz.com

Basically that halter top has small and large breast morphs of its own. It then uses EMC (Enhanced Morph Control - now called ERC or Enhanced Remote Control) so that when you turn "small" or "large" dials on your P4NW, it will also turn the "small" or "large" dials of the halter top. You can learn more about ERC at http://www.rbtwhiz.com.

Unfortionately this technique doesn't get you around the actual making morphs part. The "fit" of the clothing depends complely on your ability to make it fit with magnets or a modelling program.