I just found this service which allows users from outside of Japan to purchase from shops which do not ship internationally.
The service can be found at:
You should be able to buy Media from any online shop in Japan using this service.
Here a list of shops selling Medias:
Akibang (Site in Jp only): www.akibang.com/
Akibaoo (Site in Jp only): www.akibaoo.co.jp/
F-Shokai (Site in Jp only): www.f-shokai.co.jp/
Amazon Japan (English available): www.amazon.co.jp/
Taiyo Yuden Online Shop (Site in Jp only): http://www.thatscd-r.jp/index.htm
Media Box (Site in Jp only): http://www.media-box.jp/
Landport (Site in Jp only): http://www2.enekoshop.jp/shop/landport/Top
Mori Media (Site in Jp only but has some real cool stuff only available at this site): http://www.morimedia.jp/
*To administrators: Hope it is OK to post this in the Media forum. If not I am sorry for the extra work I give you for moving this to the right section.