The current AudioMedia magazine has an interview with a couple of the sound designers for the new Matrix films, and they mention a "prototype grain-looping program" called Inertia as one of their processing tools. That's about all that's said about it - I don't even know if it's Mac software, although they also mention MetaSynth, which is Mac-only, so Inertia may also be Mac-based.
In any case, has anyone heard of it or know if or where it's available?