There’s now a page with some basic explanation about Mango color spaces on the wiki, and a package of frames in 2K in a few different color spaces (about 250MB). There are linear EXR’s with ACES, S-Gamut and Rec. 709 chromaticities, and sRGB PNG images with and without the ACES RRT (film like look) applied.
If you want to try grading in a current version of Blender, the linear Rec. 709 EXR files are the ones to use, since those are in the color space Blender expects. the same usually goes for other applications without ACES support. Below are some images without any film like look, and without tone mapping applied to deal with bright colors, just the result you see when loading the Rec. 709 EXR files in Blender.
Here’s an updates on what we’re working on in Cycles. Up to now, the features that we’ve added for the 2.64 release are BVH build time optimizations, exclude layers, motion/UV passes, filter glossy option, a light falloff node, a fisheye lens (by Dalai Felinto), ray length access (by Agustin Benavidez), and some other small things.
There’s also now a page in the Cycles manual about Reducing Noise in renders. All of these tricks are used in production with other render engines and should apply to path tracers in general.
Currently there’s still three major features on my list to implement: motion blur, volumetric rendering and a contribution pass. We already have a vector pass now for doing motion blur in compositing, but real raytraced motion blur would be nice as well. The code for this is mostly written but work is needed to make this faster, currently it’s slowing down our raytracing kernel even if the there are no motion blurred objects.