None yet, coming soon.
The only one that is known at the moment is Intel's "Garibaldi" board. Gigabyte also has one on the way.
Considering that there will be a change of pinout on the CPU, I would wait until they decide which pinout to go with, since you won't be able to upgrade if you get an early board. Kind of like what happened with the Pentium Pro and Pentium II.