Robert Graves & Isaac Asimov – 'I, Robot Claudius'
Kurt Vonnegut & Dennis Norden – 'Laughterhouse Five'
Judy Blume & Georges Simenon – 'Are You There God? It’s Me, Maigret'
And there were some good suggestions in the comments too
Roald Dahl and Alex Garland - 'James and the Giant Beach'
Lemmony Snickett & Swansea Telephone Directory - 'A Series of Unfortunate Evans'
William Shakespeare and George Romero - 'Twelfth Night Of The Living Dead'
Isaac Asimov and Robbie Burns - 'Och, Aye, Robot'
And here are some of mine:
Thomas and Henry Gray - 'Gray's Anatomy in a Country Churchyard'
Arthur C Clark and Richard Burton - 'The 2001 Nights'
Johann Sebastian Bach and Charlotte Bronte - 'Jane Eyre on a G string'
John Keats and Eric Morecombe - 'Ode to a Greek Urn: About ten bob a week'
Can you think of any more?