A lot of Nvidia and ATI partners are starting to focus on motherboards. They want to be ready for the Fusion generation of devices, where GPU meets CPU; and they want a piece of that market.
Most of Nvidia and ATI's partners are after Nforce 730a microATX IGP motherboards, or in the case of ATI, they are after the RS780G and the same microATX layout with a single PCIe 16X slot and integrated graphics.
They just want to be ready for Intel’s CPU-GPU and AMD's Fusion, even though everyone knows that these products won't be out until 2009. However, that is only a year from now.