[Johan Ronström]

I respectfully disagree..

There should be no problem for Adobe to make an effect that works like the magic wand on each frame, with tolerance and a specified color, or the color at a specified position in the frame. Doing that for each frame is already possible in photoshop, and the results, as I have tested on five exported frames, are sufficient for what I was looking for.

There is also the Find Edges effect, that already has the ability to detect edges that could be used for continuous keying.