TSMC has been having a hard time catching up with demand for 28nm chips, thanks to Qualcomm's S4 chip which is booked up until the end of the year to their customers. But today they have announced that they are going to make a very powerful dual core Cortex A9 at 3.1 Ghz made at 28nm, that promises to be twice as fast as a 40nm dual core 2 Ghz Cortex A9 chip (which doesn't exist in mobiles right now), or 55% faster than one made at the same 28nm.
This chip will not be used for smartphones and tablets (at least not yet) and instead it will be destined for "high-performance uses", whatever that means. My guess is it will be used for stuff like servers or other special cases like that, and someone might even give it a go on the desktop or on a laptop, although I doubt it will be very successful there right now. Next year it might have more luck, but then we'll be using dual core and quad core Cortex A15 chips.
One thing that is certain is that ARM chips are advancing quickly, and Intel (and AMD) should be very worried, because the performance of ARM chips is increasing much faster than Intel can scale down and make their own chips as efficient as ARM. It won't be long now until ARM chips are good enough for a laptop. People think that even a first gen iPad was "good enough" in terms of performance, and that had a 1 Ghz Cortex A8 processor. In 2013 we're already talking about quad core 2-2.5 Ghz Cortex A15 chips, which should get dangerously close to dual core low-end Intel laptops.