As far as alternatives, I wonder if anyone has tried a screen that cycles through colors in a known sequence. Using this modulating-color screen, it might actually be easier to separate the subject because you get around the "green shirt over green screen" problem. You might even be able to use a time sampling to correct the light cast on the subject from the screen as you would have a full spectrum of response.

I could also imagine using polarized light as the backdrop as well.