By Adam Nayman No American filmmaker in recent years has put his money where his mouth is like Joseph Kahn, the director of music videos for artists including Britney Spears, Destiny’s Child, Eminem, Gwen Stefani, Katy Perry, Kylie Minogue, Mariah Carey, Lady Gaga, U2, and Wu-Tang Clan. These are big names, and for the part…