i must say the back on the rio girl is not as big as the booty girl i have a side by side comparison.
Very true, I tried very hard to make sure each of my shapes was distinctive from the others, which is why I never filled any of the request to put one shape's top with another shape's bottom. I did that sort of thing with the numbered sizes, where you can easily make a 34D-40 sim, but got burned out on those and wanted to make all the named sizes stand on their own as individual shapes.
Basically Rio was my take on a more realistic envisioning of the Booty Gal... especially since Booty was based on an exaggerated and totally non-realistic piece of sculpture, and not an actual human person or shape. The details are over at the adult site of where the original inspiration came from.
I'll be curious to see just how much Sims 3 allows us to customize the shapes... we really can't tell from what's been released so far. It will actually make me very happy if all this meshing stuff is totally unnecessary in the next game... I've always felt I was just making stuff that Maxis should have allowed for in the first place. I mean, you have infinite varieties of faces, but only 2 body shapes (fit/fat)? Ridiculous.