Hello! I have had very good experience with these sites:

www.arsenicfashions.com
www.jeannienitro.com
www.infectiousthreads.com

If you like lingerie and stockings, do a search in Amazon.com; it may be time consuming, but in the end, you'll pay less that way than buying them directly from any vendor. Search for Leg Avenue, I think you'll like their products. Good luck and happy shopping!

I have no helpful links to share but I always strongly advocate learning to sew. It's not nearly as hard as people who have never sewn think it is and once you've done it you'll never be satisfied with anything you can get "off the rack" again.

I totally feel you. i'm a size 26 (yes, a big girl) and there's never anything that's quite my style. i've learned how to make things here and there but i almost always alter my clothing somehow or embelish the shit out of it. so here we go...

there's always the occasional gothy find at www.torrid.com

but here are some tips.

ebay, ebay, ebay (you're gonna find stuff there that the average plus girl probably can't find anywhere near her)
sew, sew, sew (you'll always have a great feeling when someone asks you where you got that outfit)
target for the basics, learn to embellish, thrift shop (not a lot of big girls do this for fear of not finding their size, but i promise you, there's something out there waiting to get picked, but no one under a size 10 can wear it!

here are some more sites:

www.gothfashion.info/
www.biggalslingerie.com/ (nice gothy skirts and vinyl shit)
www.galleryserpentine.com/default.aspx (if you're willing to drop a lotta cash)
www.sizeappeal.com/default.aspx
www.whatthecraft.com/index.htm
www.bandlu.com/index.asp (kinda like a more indie torrid)
www.fashionoverdose.com/ (ditto)