Intel Six-Core CPUs are next then more Virtualization Extensions:

Virtualization.info is reporting in Q4 Intel will introduce it's first SIX-CORE CPU codenamed "Dunnington". In 2009/2010 even more exciting news for Virtualization is the inclusion of new virtualization extensions, one of which is Extended Page Tables support..which has been a performance problem in virtualization that will be fixed by the processor. All virtualization vendors are working to support these new extensions.

Nehalem, the 2009/2010 processor will also include futher inprovements for virtualized environments like replacement of the Front-Side Bus with a new QuickPath InterConnect that integrates the memory controller on the processor die, and can run two threads at the same time for each core.