I guess it was just too irresistible for Sony not to get into the HDSLR support game. However, they may be a day late and a dollar short with the pending release of EVFs from Redrock Micro and Zacuto which could possibly render the on board monitors obsolete.
The CLM-V55 is a 5 inch LCD monitor with 800×480 resolution, HDMI Connection, color peaking, and pixel magnification. The unit comes with a swivel shoe mount that fits any standard shoe, a sunhood and HDMI cable. 
The unit is powered by AC power or a battery which is sold separately. Release date in Europe – March, no announcement about a US date, but I would guess NAB. Price has not been released yet.
Sony’s Press Release:
A new clip-on LCD monitor from Sony gives DSLR camera owners a bigger, better view of their footage while shooting HD video.
The CLM-V55 is a portable video monitor featuring a high-resolution WVGA (800 x 480) (5″) LCD panel. Attaching easily to most Interchangeable Lens Digital cameras and compatible HD camcorders via the supplied adaptor, it displays video footage during shooting/playback with excellent clarity and a wide viewing angle.
The clip-on screen tilts and swivels to any angle for comfortable framing in any position – even self-shooting when you’re in the picture.
The CLM-V55 is loaded with pro-style features to help photo enthusiasts and videographers shoot high-quality HD video footage with their Interchangeable Lens Digital camera.
Pixel magnification mode assists with accurate focus confirmation, giving an enlarged pixel-perfect view of a selected portion of the Full HD image. It’s complemented by a colour peaking function that highlights the edges of accurately-focused areas of the video image.
An intuitive control wheel allows quick, positive adjustment of a wide range of monitor settings without interrupting shooting. Adjustable parameters include aspect ratio (16:9/4:3), volume, brightness, contrast, colour tone (phase), colour temp and auto dimmer. On-screen markers aid precise framing by giving precise indication of a TV’s 16:9 or 4:3 actual display area. The LCD monitor’s on-board mono speaker is complemented by a headphone jack for accurate audio monitoring during shooting.
The CLM-V55 attaches easily to a wide range of Interchangeable Lens Digital cameras from Sony and other manufacturers that support HD video shooting. The supplied adaptor simplifies mounting on any camera or HD camcorder that features an auto-lock accessory shoe or ISO shoe. Signal connection from camera to monitor is via the supplied HDMI cable, while power can be supplied using a battery pack or AC adaptor (both optional). The CLM-V55 comes with a detachable LCD hood for more comfortable viewing when shooting outdoors in bright sunlight.