Another possibility is to choose a specific genre that is pretty sure to have a range of accessible resources, like Gagaku or choose an ensemble form like Taiko or an instrument like shakuhachi.
If you opt for one of the many 'popular' genres, there are probably lots of web pages for Japanese bands, many with sound clips linked (nd there's the world of MP3, though it's probably pretty ephemeral) and sites like this one suggest that there's a LOT out there (a search for kayokyoku got that one and What is G.S.?)
Or, hey, there's even Japanese bluegrass... with Real Audio clips or this one if you have a Japanese browser.
So there's stuff out there, though you need to be a bit inventive in decideing how to think about it.