How about Anna Kendrick as Robin in the Batman movie?

Anna Kendrick currently stars with Ben Affleck in The Accountant, and the two participated in a pseudo-interview with MTV where they tease Batman and Robin.

Worth a mention is that Ben Affleck says the Batman movie isn't a done deal, and that they may not even use a Robin.

Regarding Robin, in Frank Miller's The Dark Knight Returns graphic novel, the Robin was a female named Carrie Kelley.

The Accountant opens October 14th also starring JK Simmons and Jon Bernthal.

The Batman movie looks to be 18 months out.