I'm from the US and it's easy to listen to foreign music and think of it as "one dimensional" but Yousei Telkoku is a great example of how multi-dimentional music can be. We can often be ethnocentric about this, but genres are being blended the world over.
I haven't quite found anything like them. Lots of bands in the Symphonic Metal genre come close, but not quite. What I like about Yousei Teikoku is all the different layers to the music there is. All the songs/albums have a similar sound as well. And there's plenty of variety so you don't get tired of listening. I try to tell people about them whenever I can, but most people brush it off since it's Japanese... I suppose I just need to find an american/english example of this type of music :P