Hee hee, I am having fun thinking of charming euphemisms for fat. Being an artist who specialises in adorableness helps you not mind so much about being fat, actually. Fat things are the cutest things!
Anyway, I have been looking at sites which have plus-size dresses. Because I'm from Australia, I've only been checking out sites that ship internationally, so if you live in the US you can probably find lots more. I also wasn't specifically looking for bridal dresses, although some of these site do carry those (or even better, pretty white dresses which haven't been categorised as 'bridal' and so cost half as much). I also ignored any sites which had what I considered to be overly expensive dresses. (One site had a cheery "Coming soon!" in their $200-$300 page, and a single lonely dress in their $300-$400 page.)
B & Lu
Daddy-O's (retro forties and fifties style dresses, absolutely gorgeous!)
Torrid (including some very pretty and affordable wedding dresses)
eShakti: beautiful Indian-inspired dresses that you can apparently customise as you order-- add longer sleeves, etc. Looks like a fantastic source for pretty wraps and shawls as well!
And a couple of Australian sites:
I hope this is useful!