I can't believe that you are talking about J-rock (most well known as Visual rock) and haven't mention X-japan yet, the most magnificent Visual-rock group!! where else have you seen a genius as yoshiki or hide? I'm shure that if Michael sees the X-japan 97' last live concert he won't stop drooling, mostly when yoshiki gets hurt in the hand playing the piano and he continues playing even bleeding!
following X-japan there are a lot of good Visual-kei groups or singers. Gackt's Mizerable or Mars are very good albums. and the most known bands have been mentioned before, as malice mizer, l'arc en ciel (it means rainbow in french as someone said) and dir en grey.