Thing is, if you're buying on YJ from abroad via a proxy you don't have to interact with the seller or deal with the crappy interface, you're just dealing with the proxy service. Its probably easier. There's also just such a vast availability of dope shit on there, at least as far as the designers I'm into. I dislike ebay.
Yeah Needles does do XS, and the Japanese stockists usually carry it, unsurprisingly (not always in every piece, but yes). XS pops up on Rakuten and Y! too (for example: http://global.rakuten.com/en/store/kind-u/item/576814001163/) Some stuff (cardigans, some of the shirts) seem to fit slightly smaller, so you might manage an S in those.
Ahh good call. Should have remembered they had it too. TBH I'm a bit conflicted as I really like it, but at the same time I'm getting deep into The Soloist (got a shirt, a ring, have a jacket on the way, want pants, etc.) at the moment. Choosing which flavor of eccentric hippie clothing is becoming tough