Spanks at Saks! That has a nice ring to it. Sara Blakely, who wants you all to know she is seven months pregnant and not ''lumpy'' founded Spanx, the formidable contour shaper because, and I quote, ''I didn't like the way my butt looked in white pants! Spanx was born!" There is a secret new product in the works and my guess, bathing suits, was met with a wink and a smile. Logical!