Though it's not a video feature, Panasonic has just dropped a pretty fantastic bit of firmware (via 4/3 Rumors): 

The new 2.0 firmware for the Panasonic DMC-GX8, DMC-G7 and DMC-FZ300 contains a feature that allows image focus in still images to be adjusted once the picture has already been taken — and you can save multiple copies of different focus points.

Here's an explanation of how Panasonic is achieving this capability (which is a bit different than how a company like Lytro is doing it):

Post Focus leverages Panasonic's high-speed, high-precision, 49-area DFD (Depth From Defocus) auto focus technology, and leadership in 4K Photography and Video, to capture 4K (3840 x 2160 pixels) images at 30 fps.

Essentially 4K video is helping them achieve focus in post. It's becoming more clear that this sort of technology is going to change the way we take photos by letting us worry less about getting perfect focus and more about composition and what's actually in our frames. Though we're a little ways off from seeing this implemented for video, it's going to have a huge impact once it is, especially when it can be fine-tuned to allow rack focus at any speed. 

Panasonic has also stated that this technology will be coming to the Panasonic GH4 at some point in the future, so stay tuned for that ability. You can find the firmware at the link here.

Source: Panasonic