It's not entirely clear what you're aiming at. There's a skeletal condition, often called "sunken chest", with a medical name (something along the lines of sternum excavatus), in which the sternum (i.e., the vertical "breastbone" where the fronts of the ribs come together) which might be what you're talking about. A classic example of that is a lady named Desert Rose, also called Kody. You can find her on freeones.com, and she's been in a fair number of adult videos, both before and after a boob job. Check these pics out, and let us know if that's what you're looking for . . .
BTW, who is the lady in your third post (tall, fully shaved, presumably Russian)? I saved a very nice couple of hardcore sets with her (don't know where I got them), and I've always wondered who she is.