Switronix have announced a power-solution for the Blackmagic Pocket Cinema Camera: the PocketBase. However personally I'm not too enthousiastic about what they came up with. It is larger than it needs to be and looks to be a quick mashup of a case with two off-shelf Canon LP-E6 battery plates inside. It really doesn't need to be this big with just a little more effort, but that's just my two cents.
As for the technical side, there isn't much to it. It's powered by two LP-E6 batteries. And with a regular EN-EL20 inside the camera as well, they're hot-swappable.