This is basically what I've come up with, whereby I think most everyone would relatively happy. 

First off NX is indeed a replacement for all exiting Nintendo hardware (3DS, 2DS, Wii U, etc.). In the NX era, all Nintendo games run on all the following hardware, graphics/resolution simply scale up and down. Games come on DS-sized cartridges that can range from 2GB-64GB or via the eShop. 

The chipset is the *key* to everything here, I will use a modified PowerVR GT7900 for this example, a new mobile chip. This tiny chip generates a whopping 800 GFLOPS at under 10 watts. It's perfect for microconsoles and its cheap. Low power consumption makes Nintendo engineers happy, but what about us? Well lets get to it:

NX Mario (Portable) - 600 GFLOP (downclocked GT7900), tablet-ish form factor with a few funky new ideas. Single screen touch panel. Has Nintendo OS, but can run Android apps pending Nintendo approval of said app so it has lots of extra functionality. 4GB LPDDR4 RAM w/32MB eDRAM.  $249.99 launch price.   

NX Luigi (Home Mini-Console) - Is basically the same chip as the portable above, but runs at a full 800 GFLOPS. 4GB RAM w/32MB eDRAM. Super small form factor, runs at sub-10 watts. Comes with a new funky controller that's still relatively cheap-ish. $169.99 budget priced. 

NX Bowser (Full Size Home Console) - Is basically three GT7900s in one Wii U sized casing. So that gives you a whopping 2.4 TFLOPS of horsepower, being a decent upgrade on even the PS4 and double the XB1. 12GB of RAM + 96MB eDRAM (also 3x bump). Comes with both "funky controller" and standard pro controller. $299.99 launch MSRP. 

For people who say this is too many variants, remember this is replacing *all* current Nintendo hardware. So bye bye Wii U, Wii, 3DS, 2DS, New 3DS XL, etc. etc. When you walk into the store you will see an NX section and Amiibo and that's all. If anything this is simpler for the consumer, they can just buy any NX game and play it how ever they see fit. Later on with a die shrink I think you could have a NX Toad (pocket handheld) that's the size of a current 3DS. 

Nope. Single screen tablet portable is a step back. Dual screen handheld and BC or bust.

Console controller must look like this:

Nice try. Try again.

They can tweak the portable variant in different ways, honestly I wouldn't care. I think dual screen is just a waste of battery and a redudant cost, not to mention outdated to kids today, but if Nintendo wants to keep trying to ram that down people's throats, fine. Basic idea above still remains the same. 

A tablet form factor allows for a much larger battery and more space for heat dissipation (read: you can put a much better chipset inside the casing) though, so I didn't just choose that without any thought put into it. 

Using the same chip for all variants will give Nintendo tremendous leverage in pricing, ordering in such bulk will allow them drop prices (or enjoy fatter profit margins). So they can have a pretty powerful chip, but done smartly they can get it at a good price that scales down in cost fast.

Nintendo is already back catalog DS games on the single screen Wii U, I suspect this may be a bit of a test run for the future. I play Mario Kart DS on my Wii U controller with no fuss. 

Image broken :|

Handheld. Too. Expensive.

Could be brought down in cost quickly, because Nintendo is using the same components for all three variants, they'll be asking for 20 million orders per year. That will give them leverage to drop the price. 

Keep in mind too, this isn't a rinky dink New 3DS that doesn't really do anything well but play games. For $50 more than a N3DS, you'd be getting graphics noticably above a Wii U and even opening the door to some PS4 ports (at a lower res of course). Android functionality could open the door to things like being able to watch movies, Facebook, Twitter, Instagram, etc. so I mean compared to a $700 iPad ... suddenly this thing stacks up very favorably. It would blow those cheapo $200 tablets out of the water too. 

Some details on the GPU you are citing by the way.

http://www.extremetech.com/gaming/199933-powervr-goes-4k-with-gt7900-for-game-consoles

"On paper, the GT7900 is a beast, with 512 ALU cores and enough horsepower to even challenge the low-end integrated GPU market if the drivers were capable enough. Imagination Technologies has even created an HPC edition of the Series 7 family — its first modest foray into high-end GPU-powered supercomputing. We don’t know much about the chip’s render outputs (ROPs) or its memory support, but the older Series 6 chips had up to 12 ROPS. The GT7900 could sport 32, with presumed support for at least dual-channel LPDDR4.

Quad-channel memory configurations (if they exist) could actually give this chip enough klout to rightly call itself a competitor for last-generation consoles, if it was equipped in a set-top box with a significant thermal envelope. Imagination is also looking to push the boundaries of gaming in other ways — last year the company unveiled an architecture that would incorporate a ray tracing hardware block directly into a GPU core."

For its part, Imagination Technology anticipates the GT7900 to land in micro-servers, full-size notebooks, and game consoles. It’s an impressive potential resume, but we’ll see if the ecosystem exists to support such lofty goals. If I had to guess, I’d wager this first chip is the proof-of-concept that will demonstrate the company can compete outside its traditional smartphone and tablet markets. Future cores, possibly built with support for Samsung’s nascent Wide I/O standard, will be more likely to succeed.

NX NX NX NX NX NX THIS, NX THAT, NX SALES, NX FAIL, NX SUCCES, NX NX NX NX. NX MARIO, NX GPU, NX POWER, NX CONSOLE, WII U SUCCESOR(NX)..................

Yeah another quote:

http://www.techradar.com/us/news/gaming/consoles/this-is-what-the-ps4-and-xbox-one-should-really-be-afraid-of-1286117

What we will tell you is what all of this means: Imagination's new GPUs are good news for affordable gaming and potentially bad news for the PS4 and Xbox One.

As Imagination's Alexandru Voica told TechRadar, the new GPUs have the potential "to offer the performance of the current-gen consoles, but at a lower price point."

Put three of these bad boys into one SNES or Wii U sized casing ... and voila ... now you have a console more powerful than a PS4 and really leaves the XB1 in the dust. 

There was a rumor a while ago that Nintendo was accepting hardware pitches from both AMD and PowerVR (Imagination). I'm starting to think maybe they should ditch AMD for PowerVR. These guys make the iPhone GPUs, and they make them at massive volume. 

I don't see how this will ever work.......

or how even Nintendo will make NX work with thier current, stubborn, out of date philosophies.