Casting Couch: Evan Rachel Wood as Joni Mitchell?

The question is not entirely rhetorical. As Sheila Weller's Girls Like Us, a lively history of femme popsters Carole King, Joni Mitchell and Carly Simon, is being adapted to the screen by John Sayles, I've been thinking of the dream cast for the bio-triptych about the women who blazed the path for the likes of Avril Lavigne, Beyonce and Katy Perry.