Well, I wish I could be of more help, but I do understand where your coming from. I notice that even a small is more like a child's size! I do think Rave Attic.com is supposed to get a plus size line in very soon if not already. I order from there and they're some of the most amazing looking and best fitting items I've ever owned before. I also have great luck with Kinky Intentions. I think Manifiquelingerie.com has a great selection of plus size! So does FeelingUsa.com I've not ordered from Mangifique yet, but I've been eying their stuff for a while. You could try checking out some of them
I hope you find something that you're comfortable with.
Nothings worse than having a beautiful piece of lingerie that's ill-fitting. You MIGHT could try fantasiesNlace and CyberNookie. I ordered a couple teddies and accessories from there and they have a very nice selection on both sites. I haven't really gotten deep into their items, but they're very worth the try.
Kinky Intentions, FeelingUSA and Rave Attic have yet to send me an item that I didn't feel beautiful in!