The U31SD has already showed up on the ASUS site, where one is able to pick from either a Core i5 2410M or Core i3 2310M, not forgetting having a choice of Intel integrated graphics or a 1GB GeForce GT 520M card. All three models will sport 13.3″ displays and share rather similar specifications on paper, although the U31E “loses out” among the three as it is missing a discrete graphics option. We use this term loosely, since some people are happy with a discrete graphics option alone and don’t want anything more.
Tipping the scales at a mere 3.9 pounds for the U31SD, you can be sure that the other two are no heavyweights, either. No idea on pricing or availability as at press time, but stay tuned and something official from Asus should come up soon.