[Looking at supersize / extended size clothing which is to say, clothing I can wear. Preferably modeled by fat people.]
Sanctuarie’s princess-seamed dress and wrap might work for Valentine’s Day. Or clubbing.
Dress with wrap, sketch, and swatch
I’m not feeling quite enough love to buy a dress that would require a strapless bra, but it is nice to see a dressy dress that’s machine washable!
(The description emphasizes that this dress is “definitely not for the modest”. )
Sanctuarie also carries a full line of clothing in 0x-9x, including swimsuits, lingerie, sleepwear, and even some costumes. Most of their clothing is shown on mannequins, not models.
Not all their clothing comes in all sizes (especially not in clearance) but a goodly portion of it does. I’ve never done business with them, though, so I’d be interested to hear from anyone who has.
Living ~400lbs 
I love Sanctuarie! I have ordered many items from them and have received great service, and I even live in Canada! One thing is that their tops, much like most tops for large women it seems, tend toward having huge neck holes. You can usually tell them from the pictures online though. They have some great sales! Always check the sizing measurements for each item though, because sizing can vary from item to item.
That is also a complaint of mine, whenever I venture away from my tees & hoodies & actually wear a woman’s shirt; my bra is always showing & actually it looks as if I could breastfeed without having to take the shirt off or lift it up. I can get a long-sleeve shirt with sleeves long enough to cover half my hands, but, especially if I buy something with a ‘scoop’ neck, my breasts are on display to the world. Maybe I am picky, but I would rather have a shirt cover my breasts than my hands. :-)
And I forgot to add that I cannot agree MORE about wanting to see clothes modeled by real fat people…& I DON’T mean the size 8’s, 10’s, & 12’s who are used by the fashion industry to represent ‘plus size’; they have every right to model, but they represent average-sized people, not fat people. I prefer to look at clothes on people who are at least a size 16 or 18 or larger & find that I get more ideas & a clearer vision of fat fashion by looking at bloggers who post their OOTD than by looking at most actual ‘fashion shoots.’