Not knowing what a "Global Shutter" is - what would the implications of this be if (hypothetically), it was launched on the (to be named) 7D update? Is there any benefit to the stills photography world or is it purely a video thing?
It's a purely video thing. The global shutter is the opposite of the rolling shutter. In live view, the physical shutter doesn't move, so the sensor scans the scene 24 or 30 times a second to create frames.
With a rolling shutter, the sensor scans from top to bottom, creating a distortion effect if you pan the camera, because the sensor doesn't actually capture every part of the image at the exact same time.
A global shutter captures the entire image at once, then waits 1/24 of a second before doing it again, so the distortion, or the "rolling shutter effect" is not present. Global shutters are harder and more expensive to incorporate, as the camera has to process large amounts of data at once, in a small period of time.
For still photography using a physical shutter, it makes no difference.