Nintendo has filed a patent for what might be the Nintendo NX controller.
The patent was filed in June 2015 and published this week. It describes an oval controller with a touchscreen covering its entire top side and a couple of buttons popping out of it.
In the patent, Nintendo describes the controller as
"A non-limiting example information processing apparatus comprises a housing, and a first portion of the housing is formed in an elliptical form when viewing from the front. A display panel and a touch panel constitute one main surface of the first portion. Holes are formed in left and right end portions of the display panel and the touch panel, and two operation sticks are provided through the two holes. When viewing the first portion from the front, an area except key tops of the operation sticks becomes a display area."
Of course there is no guarantee that this controller is meant for the upcoming Nintendo NX, or that it would ever find its way to production.