MTV says the Gone Girl Blu-ray comes with a "36-page children’s book story featuring the one and only Amazing Amy."
Relatedly, here's Gillian Flynn's comments about a possible sequel:
"We could pick it up and see what those crazy Dunnes are up to a few years down the road and if they got on — not well I don't think.
"I would have to have the exact same people to do it — I would want Rosamund, Ben and Fincher to do it."