https://dl.dropbox.com/u/2109634/classroom_sunsky_animation.mov
So here's another test with that classroom scene. This time without dof and moblur but with an abruptly animated physical sun. Looking at the overall render, i think it looks good. I know some will jump and say it's too fast, which is why i'll probably render it again with a slower motion of the light when i get some more time. But so far, i am pleased with the results, and by looking at the first and last couple of frames in the animation, you can notice the solution is stable. Also changed some settings and managed to get 2:30 min/frame on this one. Can't remember when was the last time i had so much fun rendering.