Leaks suggest that Intel will be dropping a new single-core Z-series Atom proc that will be the first of the family to reach 2GHz.
Granted, the Z series is the slightly lower-powered single-core chips intended for MIDs, but it's not ridiculous to assume these could find their way into a low-cost netbook or two. The new chips use the same 2.4W as the previous 1.86GHz version, allowing them to be used in the exact same thermal conditions.
Also leaked was an ultra-low-power 1.2GHz Atom, the Z515, that uses only 1.4W of power at full-speed, and just 0.65W when scaled back to 800MHz. This means it could almost be used in a mobile phone. [HKEPC (translated) via Electronista]