you have to really look a lot for decent yet fashionable full sleeved western wear, just search search and search...but it does exist...
i live in MA and in spring i went shopping for some summer stuff... found a couple of these really nice strechy/cotton fabric empire waste type frocks at filenes b similar to those that are iin in pak, but in the west here they are meant to be worn just as dresses in summer ...I wear those with striaght legged pants or any types of jeans/ khakis...these dresses go upto your knees so with pants, and long sleeves (i know its harder to find long sleeves, but if u keep looking you do come across some) they look pretty decent on a hijaban like myself..coz they hide your butt/hips and you feel totally covered up in clothing that's lose enough yet not too much and is aslo still very fashionable...
i know what you mean about the tops that are very similar in style to maternty style clothes, but the dresses i happened to get were a little fitted, even though they had empire wastes and 'chunnatein' right under the bust.