Hmm this is a hard one....probably

Males: Gackt, Hyde, Juka, Kamijo(Versailles) , Miyavi or Kaya

Females: Kanon Wakeshima, Nana Kitade, Waka(Danger Gang) or Tamaru Yukari

I always wanted to see something like a Japanese version of the G3 (G3 is guitarists Joe Satriani, Steve Vai + Guest, for those of you who don't know).
So for a Japanese G3 I'd choose:

Hizaki (in my opinion probably one of the most talented and skilled guitarists ever),
Miyavi (representing the acoustic slap guitar style),
Akira Takasaki (Loudness' guitarist, a really great player with a lot of experience)