Here’s the JAG35 batterypack. It seems like they sell a 4600 mAh version for $249 and a bigger model with 9200 mAh at $400.
To power a Canon DSLR that runs P-E6 batteries (7D, 5D, 60D) you’ll also need an adapter for $79. A cable to connect and power a Zoom H4N will cost another $19.99
And if you don’t have a free baseplate or other mounting solution you’ll probably also wanna check out their dslr stand ($79) that will attach the batterypack to your rails.
This batterypack can also power your JAG35 remote focus gears.