Thanks to a tweet from m0fe, he points out this alternative Sony Battery tray for powering up your DSLR rig with Sony NPF style batteries [Thanks m0fe]. They have a V-Mount power supply similar to this, but even cheap V-mount batteries are just out of most budgets. This tray accepts two Sony NPF970 Batteries (seen here) (but you can also use little NPF-550s) to power up fairly standard DSLR rig accessories.
The pack offers an output of 5V (for Zoom H4n), a 7V output (for powering Canon cameras), and a 12V output (for powering LCD monitors), and then clamps to a standard set of 15mm rails. The kit comes with all the necessary cables and even comes with a Canon LP-E6 dummy battery to start shooting. If you're an event shooter that needs to be fed constant power, this is one of the most affordable off the shelf solutions to power up your rig. Check it out via eBay (Click Here).
Sony NPF-970 Battery Power Supply 5V, 7V, 12V