Knowledge from knowledgeable sources tells us that Warner Music Japan has uploaded several albums to the iTunes Music Stores for Canada and the European countries (not U.S.). I’ve done a fair amount of searching, and turned up two Cibo Matto albums — Stereo Type A and Viva! La Woman. When I know more, you will know. Until then, read more for appropriate linking.

As a side note (not Warner) Epic/Sony have Puffy’s HiHi Puffy AmiYumi album up on at least the Canadian store as well. I’d recommend checking out the “Japan” and “Japanese pop” section for a few slightly more obscure titles. You could always keep your eyes on The iTunes Guide too.

Cibo Matto - Stereo Type A (1999) | iTMS link

Cibo Matto - Viva! La Woman (1996) partial album | iTMS link