Well, I think that first of all we need to create demand that models, pornstars and even surgeons will know about. If we like something, people who can do something with it need to know it to even consider the surgery.
So, let's discuss the concept first. Let's talk about it here, among people who love breasts.
Maybe sizes of Beshine and Chelsea would't be possible but I think that size of PBD could be done with at least two pairs of them.
I think that if all breasts would be separated by straps as they would be to prevent symmastia, we could create several pairs of very large breast (around PBD size). Yes, while standing, every row of breasts would lie on the one below - but wouldn't it be beautiful? :-D