Iconic American folk singer. Legendary British monarch. Few actresses could move as easily between the roles of Bob Dylan in “I’m Not There” and Queen Elizabeth I in “Elizabeth: The Golden Age” as Blanchett. For years, co-stars like Leonardo DiCaprio and George Clooney have raved about her chameleonlike ability to shape-shift at will. Though perpetually drawn back to her native Australia (where she and husband Andrew Upton will assume the mantle as co-directors of the Sydney Theater Company), Blanchett in 2007 reached even further to take on such differing parts and prove the pronouncements right all over again.