Ultrabooks are expensive. They use Intel's pricey ULV chips (with lower power consumption than the standard Atom chips) and high end design.
AMD's C-50, C-30, and Z-01 bobcat based chips are in the right area of heat and power consumption to be used in an ultrabook like device, but that's neglecting the second part of the ultra book...high end design. When you get into Macbook Air quality materials, you might as well spend the extra $200-$300 it costs for an Intel processor over an AMD at that point and get 5x the cpu performance (and the hd3000 is roughly equivalent to the E-350's gpu, so it should destroy the Z-01's).
This represents probably about the thinnest design out there using AMD, it's using their lowest power processor, the Z-01 tablet chip.
http://www.amazon.com/MSI-WindPad-11.../dp/B0056EXUBQ
Or double the price, and get the better designed Samsung Series 7 slate, representing the thinnest in Intel's ULV chip designs.
http://www.amazon.com/Samsung-XE700T...1215769&sr=1-2
However, once Ivy Bridge comes out, I expect Intel to focus much more heavily on its LV and ULV chips, and Windows tablets will be much more common at the high end. I also expect AMD's Z-01 (Desna) successor will go into a lot of cheaper Windows tablets.
Llano's power consumption is wayyy too high for an ultrabook. Ivy bridge ULV chips will best it in cpu performance, be decent in GPU performance, and use far less power.
(
http://www.techspot.com/review/441-msi-windpad-110w-windows-8/ devices like this will be very common in 6 months, imo)
Ultrabooks = high performance netbooks.
AMD doesn't have high performance low power chips.
Ergo, AMD ultrabooks are things like:
http://www.laptopmag.com/review/laptop/lenovo-ideapad-s205.aspx