I'd say Yahoo!Japan auctions, but I've never actually been able to navigate the middleman sites so DDD: Sometimes, people in the community run group auctions though, so I'll keep you in mind when I see the plush you're looking for. c:

A lot of people in that community are really...intense collectors. |D I have no idea how they can collect so many. OTL

ALSO *SCREAMS* I SEE THAT LINK. Aililui's really awesome, and they always bring in so many nice stuff. *_* O-oho...I see that Glaceon Pokedoll...