I love it as well and remember seeing it i think in the street style section. might be hard to track down though . . . but it's a great pic for inspiration - the whole outfit is awesome.
I *think* that's a pic from Sartorialist. INC makes dresses in a similiar shape, but I haven't seen a similiar pattern. I know every once in a while juniors stores (F21, Charlotte Russe, Wet Seal) has similiar dresses