Personally I think there won't be "Next Nintendo Home Console". My guess is they're going to merge handhelds and home consoles into one device and go portable only. Something like Wii U portable (I.e Power PC based), backwards compatible with the 3DS/DS, potentially, digital only.
Of course, like I said, this is my personal guess, but just a quick look at the total sales of home vs handheld Nintendo consoles and that would make sense from the business point of view.
Also there's plenty of clues in the design of the Wii U itself. That would explain why the Wii U consumes so little power (less than Wii) and why Nintendo was so obsessed with power consumption (for home consoles it makes no sense). Plus the OS CPU is ARM based, just like 3DS/DS and Wii U, while connected to the TV is essentially two screen system, just like 3DS/DS. The game pad, apart from camera, has motion sensor built in, so technically, no extra peripherals are required and it's still compatible with the Wiimote. The 5GHz wireless video streaming is there and it could be easly reversed, sending signal to the Wii U, therefore to TV, or directly to TV with some HDMI dongle.
Of course I'm talking about 3-4 years old hardware (if not older than that), which with every year becomes cheaper and more power efficient.

The point I'making is that is very big discount for newly arrived consoles on market.