as far as jpop and the possibility of major label jrock is concerned, it will be with watching TOFU records. But have you seen, for instance, Asian Man Record's catalogue?
http://www.asianmanrecords.com/
Asian Man are more well known for Alkaline Trio, but they get a lot of asian [punk/new wave] acts on their distribution. Polysics, Nicotine, Potshot were all on that label. There's also another label that just wholesale imports (really, really indies) punk bands, but I'd have to dig through some boxes to grab one of their LPs. Alternative Tentacles has also hosted a fair number of Japanese acts, but I mean, none of these labels are either positioned correctly or equipped to deal with visual kei. They know how to market to independent "punk" music consumers and for one of them to try to sell something like a Gackt or a Dir en grey really wouldn't work. They are, however, playing the game and at the college level doing a pretty good job. Asian Man gets a good deal of distribution. That second label whose name I can't remember not as much, but that's also largely due to the fact that they only sell vinyl.
Things could change in the next few years, and I would not be suprised to see a Japanese band break the charts sometime in the next 5. But it's going to take one of these major labels taking a risk monetarily for it to happen, I think. But I do think you're right. And I mean, Japanese bands do have pretty intense schedules. To be big in multiple continents and maintain it is a pretty big strain.
anyway, yeah! always a pleasure XD