Stephenie Meyer was working on a version of Twilight, where the story is told in Edward's view, called Midnight Sun. Notice the past tense. She is no longer going to publish Midnight Sun, because someone posted it on the internet, ilegally. She has sworn to write SOMETHING, but it most likely is NOT going to be a continuation or the books. A special version, told a different way, or an untold part to the story. She has yet to release the title, yet alone what it's going to be. But rest assured, she will do something more with Twilight. I do not know when, but I DO know that it'll be a long time before it is coming out. Hope that this helped!
