So Nikon's new prez says they will showcase a new concept camera this year. Obviously the best time to do that would be at the Photokina2010 trade show in September. I also think that it's a pretty safe bet to say that it will be Nikon's first EVIL(mirrorless) camera.
Remember that Sony did the same thing with it's EVIL concept camera in Feb. at PMA. The production versions of the NEX cameras really weren't any different. It took about 4months for Sony to put their "concept" cameras in stores. I'm thinking Nikon will put their "concept" camera in stores around December.
But what if the concept camera turns out to be the mysterious MX camera and it actually does turnout to be a new Nikon medium format system?!? I doubt that though since Nikon would make a butt load more money with an EVIL cam geared towards "amateurs" rather than an expensive medium format cam for "pros".