The casting for the play Harry Potter and the Cursed Child (set many years after the books with adult characters) has just been announced:

http://www.bbc.co.uk/news/entertainment-arts-35149864

I suspect that there will be a LOT of completely unjustified fan-wank about the casting for Hermione.

Since I really don't want to read all seven books again to check, would I be right to suspect that there is no description of Hermione that actually contradicts this? Her first description in Philosophers Stone says she has bushy brown hair, but hair colour and style are very variable for women...

Update - and if I'd actually read more than the first paragraph of the article I linked to I would have seen that Rowling explicitly says that there is nothing in the books that contradicts this.