There may still be Japanese edition novels or manga available in US site, not sure.

There are some Japanese ebooks on the US Amazon site. I bought Car of the Dead, a Kindle short story for only 3 bucks. It's a horror (zombie) story by Otsuichi, who is a fairly popular writer in Japan (he's also directed movies). It was one of the earliest things I read, after advancing from graded readers, and Satori Reader. It's a pretty easy read if you already read most of stories/articles from Satori Reader.

You can also buy Harry Potter in Japanese from the US site, which was a little harder because of all the fantasy terminology.