...but none of them can fix the analog hole.
Couple, three far out 'fixes' for the analog hole.
LCD refresh
You know how sometimes when you make a video of a PC it comes out really bad; dim and with rolling lines thru it? Usually this is a function of the display technology used + PC's refresh rate + the cameras shutter speed.
If you look at the individual frames, you would see many blank screen or partially blank screen frames. The brighter the screen of the PC, the faster the shutter of the cell phone, and the greater the chance of catching the PC during a blanking interval.
And unlike CRT's or even plasmas, LCD screens have little persistence in the luminance of their pixels. They switch on and off quickly and with little effect due to hysteresis. They also have a far wider range of refresh rates available, from 30hz to 240hz. I wonder if a rate could be found that would substantially degrade the picture?
Macrovision ripoff
You may have tried to copy a blockbuster VHS tape and been disappointed with the result. That is likely due to Macrovision protection, a scheme by which the auto gain of the recorder is fooled by a extremely quick and false signal that causes the recorder to constantly adjust the gain, leading to a crappy recording.
Likewise, perhaps a subliminal signal, to quick to be perceived by our eyes, could be introduced that would cause the cellphone camera to adjust by lowering the gain and degrading the video.
Key Lemon
Taking a different approach, there is a face recognition/authentication single sign-on program called Key Lemon, which can automatically lock the session if it no longer detects your face directly in front of the screen. It also records people who try to enter your session. Although, I'm sure someone could stay in front of the screen and record at the same time, I wonder if it could be modified to lock a session if it sees a cell phone in the frame.
I'm sure even that could be beat, but remember the people who take these videos have not figured out how to beat these systems ahead of time, it's not like they are expecting J-Z to walk into an elevator and beat someone up on camera. So just a decent deterrent that makes it harder than just point and shoot may be all you need to make someone think twice.