Tailor is the best solution for wide variety of morphs, but if breast size is your chief concern, there a couple other possibilities at the MP here. First, there is a set of magnets that will mirror V2 breast sizes (by the3dwizard, I think). Second, if you are primarily interested in larger breasts, you could get wyrmmaster's Voluptuous Vicki, which has a whole system for enlarging and positioning the breasts. VVicki also has an add-on product that contains pose files that will conform much of the commercially available clothing to VVicki.