There are some ultra low power dual core Sandy Bridge CPUs in the pipeline. Just don't expect to see them in 'Netbooks. That's mostly based on price and performance. You will see them in CULV ultra portable notebooks.Intel’s Sandy Bridge: Upheaval in the Mobile Landscape
Don't forget about the ultra low voltage Arrandale's already out. Lenovo U160
and Lenovo U260
would be some examples.