As far as video recording goes, it need not be done in real time. One picture every second would be adequate to determine what was going on at the time. This would allow for a long duration recording without an undue demand on memory space.
The same goes for displays. Instead of trying to shoot the cockpit displays with a camera, why not capture the actual displays and record them? Again, once per second would be adequate to determine what was going on, and yet not require an inexorbitant amount of memory to accomplish.
All of these captures (cockpit cam plus each display - 6, 8, what?) could be recorded on a separate memory module in the FDR, or in a separate Video Data Recorder similar to the FDR. As has been pointed out, the technology certainly now exists. And one capture per second for each camera/display would be sufficient.
Thoughts?