The news is that NVIDIA is at least examining and commenting on patches concerning the open-source efforts to implement support for features that would allow NVIDIA Optimus to work under Linux. Specifically, Aaron Plattner, a well known NVIDIA Linux engineer, has been commenting on patches recently concerning provider support for RandR 1.5. The provider object support for the Resize and Rotate extension would allow for output slaving, DRI2 offloading, GPU switching, and multi-GPU rendering.
From this video you can see it in action of the GPU offloading and USB hot-plugging side of things.
Here and here are the recent comments by NVIDIA's Aaron Plattner about this work. There's no word of NVIDIA comitting to this support or any other new features, but at least they're investigating it. How many AMD Catalyst developers have publicly commented on the patches to date? Zero.
It was also back in January that another NVIDIA Linux engineer talked of NVIDIA Optimus Linux possibilities, that time when it came to the DMA-BUF infrastructure for the Linux kernel.