Not going to happen. It will be 3D, like it should. The era of 2D Zelda is over.
They'll likely use the Ocarina 3D engine as a base, but it'll look noticeably different from it. Perhaps not as much as Wind Waker and TP (they use the same engine), but different enough. I personally do not care what style they use on the 3DS, as they as they use the realistic look for the WiiU title.
Zelda is a series Nintendo primarily uses to show off what their technology can do, that means it will be top notch for whatever system it releases on. This is true for every Zelda title to date. They can't afford to have a 2D Zelda on 3DS, it'll affect their and the series' image. This is especially true if they would go sprite-based, they really can't sell that next to Super Mario 3D Land (or Ocarina of Time 3D), as the new Zelda game's production value would seem extremely low in comparison and in would in no way play to the strenghts of the console.
At the absolute most, they can go '2.5D' like Phantom Hourglass and Spirit Tracks, but I don't see that happening either. The only reason they did that on DS was so that they could implement the Stylus controls in an effective way. That's impossible now (because the touchscreen isn't 3D), so there wouldn't be a point to do in this style!
No, 3D Zelda it's going to be.