Nvidia's new K8-supporting chip for the Advanced Micro Devices (AMD) platform, the Crush K8, will come as a single chip solution with the AGP controller interface integrated into the south bridge chip (media communications processor, MCP). Nvidia demonstrated the product for the first time to certain customers at Comdex Fall 2002.
Whether this is a positive or negative change in design remains to be seen, in the other hand the rest of chipset makers such as VIA, SiS and even ATI (that also plans to release a Hammer chipset) have said they will go for the traditional northbridge and southbridge combination which gives more flexibility in the long run.
As far as I know some of the Athlon 64 and Opteron machines running on Comdex were using NVIDIA chipsets, so I'd say we could expect a very solid product by time of release. Talking of NVIDIA chips, a few nForce2 based mobos are available right now.