Well, Victor Hugo (Les Mis) wrote nude, but apparently he had a servant take his clothes so he'd have nothing to do but write.
James Whitcomb Riley (poet) did the same so he wouldn't go to the bar.
Edmond Rostand (Playwright, and poet) did it so no one would interrupt him
Hemingway wrote nude, standing up (which obviously find to be the odd part). Also his cousin founded a nudist club in the UK.
DH Lawrence (Lady Chatterley's Lover) "liked to climb mulberry trees, in the nude, before coming down to write."
And Agatha Christie apparently wrote nude as well.