This has passed well under my radar, but it's a very interesting product for certain kinds of photography:
The new Olympus EE-1 dot sight will make you feel like on a shooting range | Photo Rumors
I've been involved some heated discussions around electronic viewfinders and action photography, but this device will, if it works as advertised, be a big help for those who want to shoot birds in flight, air shows and racing vehicles with a mirrorless camera. Basically, it's an optical viewfinder to place in the viewfinder, making it easier to track subjects that change direction or speed abruptly. In addition, one will be able to see subjects that have disappeared from the viewfinder more easily, since it's a rather open solution, making it easier to "catch up". I wonder how it handles parallax error. Also, one would need the hybrid AF of the E-M1 to be sure about focus tracking, and even then... I'm not sure.
It would be interesting to hear from anybody who has tried it.