Simon and Schuster website has been updated with a listing for a new Star Trek ebook coming in October: Vanguard: In Tempest's Wake, by Dayton Ward. Although according to Dayton Ward's response to the news on twitter, it should actually be TOS rather than Vanguard (which is due to come to a conclusion with the imminent release of Storming Heaven).
Hopefully this is also an indication that last October's release of the Typhon Pact ebook, The Struggle Within, was also a success. And hopefully if this one does well too, we might be lucky enough for this to be made more than annual event?!