I’ve had this site book-marked for a while. It lists online plus-size stores at the “mall” main page: http://www.elegantplus.com/Plus-Size-Clothing-Mall.htm

And there’s a special page for those stores that carry sizes over 26/28: http://www.elegantplus.com/Mall/supersize.htm

I haven't shopped many of these stores online. I usually buy from LB, Roamans or Junonia. As for Junonia, they can be expensive, but I’ve only found quality items there. I have only bought pants and (Quikwik) underwear from them, but they’ve lasted me years. There was some light mending, but they were/are still mendable! (my Lane Bryant/Roamans pants, OTOH, wear away too easily in the thigh area.)

I also notice that the supersize link also lists Catherine's and FashionBug Plus, two stores I've made "live" purchases from back home in Staten Island.