So The Witcher 2's video pitch to publishers was leaked last week, and we've all been asking a lot of questions. CD Projekt have now answered some of them. No, that's not the final voice acting, and yes, it's a new engine: "The game does not use the Aurora Engine anymore. We developed a brand new engine dedicated to creating games with the design and features we love. The new engine is fully scalable and, well… kicks ass."
We contacted CD Projekt to ask even more questions, but they've declined to say any more at present. (Although RPS will be first in the queue, obviously.)