I long ago though about using a dual channel version of something like this to simultaneously vary the microphone angle and spacing for a stereo pair. Doing that with those two parameters linked, based upon the Stereo Zoom relationships for the polar pattern, one could input the desired Stereo Recording Angle and then sweep the mic pair through all spacing/angle variations which achieve that SRA. Would be really interesting to listen to that seamless change, effectively providing a real-world, real-time, powered stereo zoom of all equivalent SRA options. And, if quiet enough in operation, it could make for an interesting stereo effect while recording!