Some information about NVIDIA's G80 GPU has been published over at X-bit Labs today. They claim this DirectX 10 capable chip will feature 48 pixel shaders and an unknown number of vertex shaders.
The chip is still expected to support feature-set of DirectX 10 along with Shader Model 4.0, even though it will not take advantage of the unified processors that can compute both pixel and vertex shaders.
Microsoft Corp. pushes unified shader language for pixel and vertex shaders in its Xbox 360 game console ad well as graphics API of Windows Longhorn – Windows Graphics Foundation 2.0, which is sometimes referred as the DirectX 10. As a result of that graphics hardware designers should deliver their chips with unified shader engines at some point in future in order to more efficiently support the new API. However, previously Nvidia Corp. expressed opinions that it would make sense to release architecture with unified shader processors “when it makes sense”.
A couple of months ago NVIDIA said they will do a unified architecture when it makes sense. More details over here.