I found a couple of sites for the scarves, etc. for those interested.
For the full costumes, there's a ebay seller that will give discounts for buying in bulk and the price per costume is not bad -- $14-40 plus $18 for shipping. (They even have plus sizes.)
http://stores.ebay.com/kaimono-shop (Dibs on the first blue one on page 4!) Their rating seems pretty good.
This site has some really pretty costumes and hip scarves at nice prices. Only problem is I have no idea how reliable they are (but I've had super luck with online purchases, so don't worry that much) nor what their shipping charges are.
I'm thinking that maybe we could all get together to order from a site and see what kind of discount they would give us re shipping, etc. Might be fun.