Very interesting. To me it's part cafe racer, part chopper, and has an extreme "mechanical" feel to it. Definitely an art project, and a cool one at that. Love that big 4-leading-shoe front brake. Is that a Grimeca?
Those also look like vintage shocks, maybe Boge/Mulholland or Girling?
Yes, it is Brad Pitt's bike, built by former Zero Gravity creator Shinya Kimura, now owner of Chabott Enginering in Azuza, California.
That's a replica four leading shoe drum by Fontana.
His bikes run about $40K.
BTW, this was all featured in this month's Cafe Racer Magazine.
Mr. Pitt went down on one of his bikes today. At least it wasn't this one. Lots of photos by searching for Brad Pitt + Motorcycles if you're into that kind of thing. Got to give the guy credit for having a stern talk to the photographer that cut him off.