I've read that thread before(so I know it's no longer allowed), but his question gave me an idea, and it involves something slightly different.
Say the under implant is small and flattened, maybe an inch thick and 4 inches in diameter, then a normal round large implant is put over the muscles, sort of giving the breast a more projected/swollen look.
I drew a picture to illustrate. As the lower right view illutsrates, it's actually going for a different look.
ribcage/humorous blue-green, pectoral muscle red.
I'd like to see a photo example of the 'two-scoop' effect also.