My favorite movie about writer (and I'm sure you know about it already) has
to be the Coen Brothers' BARTON FINK --  though it is about a really bad writer.
Other titles to consider:
Sam Fuller's THE BIG RED ONE -- which features a chrarter loosley based on
Fuller himself, who is writing a book about his WWII experiences in the titular
regiment.
Rob Reiner's MISERY & the upcoming SECRET WINDOW -- these last two are based
on works by Stephen King and feature writers trapped (literally) by their past
successes.
Just a couple of smaller, genre (i.e. "Horror" and War) films you might not
have considered.
Good Luck!
Fred Holliday

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