"Also in development is a focal length reducer for EF lenses, this will be announced with the 20mp EOS M camera"
That is something you hear about more in astronomy. But a 0.8 focal reducer that would turn your 10-22 3.5-4.5 into, say, a 8-18 2.8 - 3.6 would be interesting. A Meade or Celestron focal reducer costs in the neighborhood of $100. Count on the Canon being $300, maybe. Because it is Canon, and because it has the EOS electronic connections.
Am I right in thinking that such a reducer would also increase the effective light-gathering capability of a lens, as the same image will be projected on a smaller area? This would mean an f/2.8 lens could behave something like an f/2.2 lens (depending on efficiency) when mounted to the reducer (in terms of light gathering).
This already exists, so, you can see what it would essentially do: http://www.metabones.com/buy-speed-booster
So, for the EF to NEX one, it makes the lens .71x wider while increasing the aperture by a stop (technically a little more). It essentially creates a full-frame approximation while using an adapter and APS-C sensor. There would be some short-comings (AF being one, I would imagine), but a great combo for landscape and video no doubt. The Metabones one is all the rage with people shooting on GH2's and GH3's
As you can see, the price is as much as a mirrorless body. Can't imagine Canon selling it as a loss-leader, so, expect it to be $5-600 if it's as good as the Metabones one.