AMD just tweeted that they are supplying the graphics hardware for the new Wii U. Unfortunately, they do not specify which model of hardware or any specs whatsoever, but they do say it is from the "HD" series of graphics cards, which means their 5000 and 6000 series. If that's the case, the WiiU might be the first DX11 capable console.
http://www.marketwire.com/press-release/amd-nintendo-join-forces-creating-new-way-enjoy-console-gaming-entertainment-nyse-amd-1523972.htm
http://www.marketwire.com/press-release/amd-nintendo-join-forces-creating-new-way-enjoy-console-gaming-entertainment-nyse-amd-1523972.htm