Optimus as implemented by NV is built heavily around the Vista/Win7 architecture. That doesn't translate to the Linux in any meaningful way.
Hence it's very expensive to port to Linux where it isn't going to be a clear differentiator that results in return on investment. The most likely source of improvements will be from the the efforts of avilella earlier in this thread. But you won't get NV's driver working on that until there is a generic architecture that supports it in a vendor neutral and vendor friendly way.