Google 'Gan Ban' - record label/importer/promoter/etc that does club nights.
Their last big night saw the likes of Justice, Boys Noize, Vitalic, Basmement Jaxx and a few other big names all on the one night. That of course was quite a big event but they do other smaller weekly events too from what I have been told.
I have never been but have received some advice from locals as I am planning my second trip to Japan and plan on doing a lot more partying this time
