During Orson Scott Card's recent L.A. Festival of Books appearance, he answered a number of questions regarding the upcoming Ender's Game movie. He revealed that he will be having a small cameo, but that he opted for a voice-over rather than an on-screen appearance, because he "didn't want to be a distraction."
Card further revealed that he and co-author Aaron Johnston have developed the storyline for a new work of fiction set during the Second Formic War, "which is the one that really stars Mazer Rackham." No contracts are yet in place for this piece of work.
In an interesting twist, Card has revealed his desire to create a movie or TV show based off of the Formic Wars. However, because of the rights situation, this series would not be able to include any of the Ender's Game characters, including Mazer Rackham, who would be replaced by "an unnamed half-Maori."
With regards to future movies, Card encouraged fans to see Ender's Game: "If you’d like to see some of the much more filmable works from me, go to 'Ender's Game!' . . . Because if ‘Ender’s Game’ does not do well, you know how Hollywood works."
For more information on the future of the Enderverse, the differences between Ender's Game the book and the movie, visit Ender's Ansible.