I have proof that it is Leiji Matsumoto without a 
doubt (*whew* took a little looking). In a radio 
interview with krcw (public radio station in Los 
Angeles) members of the band said they wanted 
Leiji Matsumoto to do the videos because they 
were big fans of his work when they were kids. 

Interview is rather good (with some of their 
tracks) on real player at this site: 

http://daftpunknet.multimania.com/

(for the info on Matsumoto, forward to about 20 
minutes in). You can also download the videos 
here.

Still no word on whether it was done with cels or 
not (would be nice, yes?).

Wendy