UPDATE 5:48pm PT - Intel released an additional statement after this blog was posted. "We are not seeking any SLI concession from Nvidia in exchange for granting any Nehalem license rights to Nvidia," the company said.
I'm no insider, but at least one thing seems obvious: Intel dislikes the idea of selling boards that promote AMD sales, especially profitable ones. Are NVidia high-end mobos and chipsets taking that much business away? Can't be too much, since non-SLI users are the vast majority, and an Intel chip goes in anyway. I'd also expect them not to encourage NVidia to have to support the latest AMD chips to stay close behind. So I wonder if Intel is twisting arms or not.
Of course, business isn't always numbers, there's egos looming in those boardrooms.