Perhaps not quite as heavy as previously thought:
"The OM-D is expected to feature a magnesium, weather-sealed body that weighs 373 grams for just te body. It will sport a 16-megapixel sensor optimized for High Dynamic Range, FAST AF, 3D tracking, and a five-axis image stabilizer inside the body. It offers ISO options of 200 up to 25,600, a built-in digital viewfinder with 1.44 million dots resolution, and a 3-inch 610,000 pixel OLED tilting preview screen.
The camera will likely be unveiled at Olympus’ February 8 press event. Olympus recently trademarked the OM-D name and launched an ad campaign highlighting the letters “O” and “M.” The company also has placed a “coming soon” teaser on its website."
I have to say that I am excited about this camera. Looks like a nice upgrade to the E-P2 that I've been using. Olympus has a really nice range of lenses for their m4/3 cameras too, which is a big plus when compared with some of the other mirrorless system cameras.