Ray T writes in and shares this updated version of the Canon 5D Mark II anti-twist plate [Thanks Ray]. This time, the new plate supports pin location for both the Canon 5D Mark II and even Canon's latest 5D Mark III. Anti-twist plates are important for those who don't want their cameras to shift when using items such as a Follow Focus system. The little pins fit into the alignment hole under the camera body. The plate then offers multiple threaded holes to secure your QR plates with two bolts (instead of one).
This Anti-Twist Plate now works as an HDMI cable protector with a 6 cable pinch that attaches to the side of the baseplate. If you haven't dealt with HDMI cables much, they consistently come loose of get yanked out of the camera body. At times, this cable can even cause some damage to the camera's internal HDMI port (an expensive fix). HDMI locks prevent cable shifting once it's connected to the cameras HDMI input. A cable lock like this will also save you from having to buy new HDMI cables from the constant damage.
From what I can tell, if you don't use the alignment pins, this baseplate might mount to other cameras as an HDMI lock. It also brags about how it can connect up to 6 cables at a time unlike other cable lock solutions. 6 simultaneous cable locks appears to be overkill because I doubt you'll be connecting your USB/AV port at the same time you connect your HDMI port, and also have a PC sync cord for flash photography. At most I think three locks would have been suffice - a shutter cable (5D3 starts video now), Microphone cable, and HDMI.
It is what it is, and though it will run you just under $50 bucks, it's priced cheaper than some other HDMI lock solutions and still doubles as a solid anti-twist plate. Check out the updated HDMI protector / Anti-Twist Plate over at CoolLCD (Click Here).
Canon 5D Mark II & 5D Mark III Anti Twist Plate with HDMI Lock