It could work as a slider probably. That shape that they have is referred to as a 'belly tuck', at least where I live. The chest looks bigger, because the stomach goes more inward, compared to the rest of the chest.
The slider could increase that shape, and moving it the other way could give them a more.. pregnant look? I know that would be abused, but that would be the opposite of a tuck in the belly, right? LOL
I dunno, I like it, but you don't need a new model for it, I don't think.