We heard that PCIe motherboards are far from a piace of cake to develop, and that R&D departments have to put some extra effort in to get these boards up and running.
We don't know what exactly is harder to make, but we know that everybody agrees that AGP motherboards are much easier. Can it be because PCIe lanes are not configurable and you can configure them in various configurations as you usually have 20 to 22 lanes?
So we can only speculate as to how hard it is to make SLI boards, and we recall that Nvidia gave the green light only to tier one motherboard manufacturers to build such motherboards. Just now, tier two companies have permission to make SLI boards for Nvidia and we can expect these soon.
Nforce 4 Ultra motherboards are sampling, but there are no quantities available yet. Via K8T890 boards are hard to find, and only Intel has managed to make 915 and 925 just about right. ยต