... I wonder if it is possible (... or could be made into a feature ...)
to load custom designed frame guides into the camera.
As DOP or Director, one could design a visual grid and provide it as a vector eps or an image format with alpha channel.
It might be self stretching to the recording resolution / ratio or stick on the center.
Ideally, one would upload a couple of them and be able to choose for a specific shot.
Whats your thinking ... ?