We don't know if there's a Robin Williams biopic in the works, but actor Jamie Costa should be cast as the lead stat.
Jamie looks like a young Robin Williams, and he does a SPOT-ON impression. He just released a video called "Robin Test Footage Scene" on his YouTube channel.
(“Robin” is a fan project that Jamie Costa is heading along with Danny Peykoff, James McLean, and Jake Lewis.)
In the clip, he's playing a "Mork and Mindy"-era Robin, getting his makeup done for the show, when an actress playing Pam Dawber comes in to tell him that John Belushi just died.
It's a dramatic scene with very little comedy, and it shows that Jamie is more than just an impressionist. And the Internet is already convinced that he SHOULD play Robin.