One of the worst things that can happen to a writer is to have what you think is an amazingly original idea, only to find it has already been done.
It has happened to me on numerous occasions. Maybe I should get out more... or less, given that one theory is that in the always-connected society, we're all being exposed to pretty much the same information, so therefore we're more likely to come up with the same ideas.
Rob Hood had these words of consolation for me, which I'm sure he won't mind me sharing with you...
"Originality comes from the way an individual author reworks the ideas and plot elements, and, most importantly, the characters he/she creates to carry the action. In Shakespeare's time the idea of writing a 'new' story in the modern sense was considered ridiculous and worthless. Stories carried tradition; the beauty and significance was found in the way the old ideas were filtered through a contemporary sensibility. Shakespeare never wrote a single 'original' story, yet he was and is one of the most original authors ever to have put pen to paper!"
Luckily for British director Michael Bartlett, he got the jump on horror-meister George Romero: The Zombie Diaries is finished, while Romero's Diary of the Dead has only just gone into production.
You can read what Bartlett had to say about the Romero link here, and the full feature here.