I was looking through the new messages at Buxom Life, saw Stacia Zabaleta's post on the "Introduction" thread, and was happy to find out that she has clothing for prim breast users at her store, Gatherings.
I went looking (accompanied by Foxbean, yay!), and sure enough, there it was. Some outfits are more daring than I'm comfortable with, but there's a variety of choices, and I bought some more modest items and some others that I might not normally buy, save that I've seen them worn, and they look very good.
So, makers of prim breasts and prim breast-related items (not just clothing--I have hopes that someone will start making prim breast-friendly animations), here's another example. When trying to get your name before the prim breast using public, come to Buxom Life and introduce yourself.