Rachmaninoff had anormally large hand too
Not that big actually. Van Cliburn propably had bigger hands but Rach could stretch his unusually long pinkies to a 90 degree angle and that´s why he could play 13:s.
I still wonder why he rolled 10:s in a way that someone with average hands would do.
Just listen to his Rach 3
Rach was also a big guy in general, being 6´5 tall he was more then a head taller then most other men in his days.
More composers with dissabilites would be
Bruckner and Satie who both had Aspergers syndrome, a mild form of Autism.