...then you're in luck! As announced in Publishers Weekly:
Alvina Ling at Little, Brown has bought world rights for Chris Barton and Tom Lichtenheld’s companion picture book to Shark vs. Train, for publication in spring 2013. Erin Murphy at Erin Murphy Literary Agency is the agent for the author, and Amy Rennert at the Amy Rennert Agency is the agent for the artist.
The new book is scheduled for spring 2013. Shark Vs. Train is the New York Times bestselling book, named to several major "best of the year" lists last year, that asks the question: Who will win? We know the answer: Chris Barton!