As also mentioned by the crew over at the DailyTech today; alongside the launch of Socket F Opterons AMD have said that their native Quad-core chips (dubbed K8L) have been taped out! We will hopefully see them emerge by early Q3 next yr.
The company's press release claims "AMD plans to deliver to customers in mid-2007 native Quad-Core AMD Opteron processors that incorporate four processor cores on a single die of silicon." For a little historical perspective, AMD's dual-core Opteron was taped out in June 2004, and then officially introduced in late April, 2005.
The press release further adds that the quad-core Opteron will be compatible with the dual-core DDR2 Opteron motherboards. The news of backwards compatibility with existing DDR2 Opteron motherboards is in line with AMD's previous announcements on its other platforms. On roadmaps earlier this year the company also claimed that AM3 processors would be compatible with AM2 motherboards.