i really don't get you and your Console-Handheld hybrid idea.
Nintendo won't do this simply because they wouldn't have something to lay on in case one of those systems fails to take off (ala GC-GBA, WiiU-3DS)
and besides, like others have mentioned, Ninty's take on handheld and console installments of certain franchises are different, like Zelda for example, 3DS could run Twilight Princess and Skyward Sword, but they chose to put something like A Link Between Worlds.

The 3DS still can't quite run exact GameCube level visuals. You could do something like Skyward Sword on the 3DS, but it would have to be downgraded in a lot of ways.

3DS is better off coping with a 3D Zelda like Ocarina of Time but enhancing that instead.

This will change with the next Nintendo handheld though, it will be able to run a 3D Zelda that significantly would outperform even the most recent Skyward Sword with ease.

You start to reach a level of graphics where I think it's "satisfactory" to a lot of people. 

3DS can already run this:

but you have to understand that Nintendo rathers it getting this:

It can't run TP/Skyward Sword just yet. They'd have to scale down the game quite a bit. The next Nintendo handheld though ... will be able to run that in its sleep. 

The three examples I posted are pretty modest actually, those are all Wii/GCN level visuals sans the resolution more or less, the next Nintendo console will be able to push far higher levels of poly models/lighting effects/texture quality etc. 

It would probably be able to handle some Wii U ports like NSMBU, DKC: Tropical Freeze, and even Mario 3D World without too much having to be scaled down (at least at a resolution like 540p). 

I personally believe that is why they introduced the tablet controller for Wii U. At this point, they may be possibly considering an amalgamation of their handhelds/console, allowing it portable yet provide t.v connection.
With the rate of mobile tech in the next 5-6 years, they may be able to create a tablet with that sort of connectivity and power comparable to WiiU vs 360/PS3 in terms of it's graphic capabilities against what the Xbone/PS4 can currently do.

Hence motion controls and the entire GamePad concept. Not to mention their focus on local multiplayer.

The Vita today is already $199.99 ... assuming the next Nintendo handheld is a go for fall 2015 at the earliest ... the type of chip/performance they'd be able to get, even at a fairly affordable price would be quite impressive I have to think.

Sorry but this is a very close minded idea. There will still be ways for Nintendo to evolve their console games and make them different and impossible to achieve for their future handheld.

Technology is always evolving. Currently we have virtual reality and real time cloud based gaming available. Nintendo has unlimited resources of imagination and creativity that can benefit from those in the future and other unforeseen advancements in technology.

I think the PSP and the Vita has proven this theory wrong.
Handheld gaming isnt about getting a console experience on the move, its an entirely different ecosystem.

There may be a future Nintendo console, though I suspect it may be something very, very different from the past and will be something tailored more towards the Western market (as the Japanese console business is dead, yes, even with little things like the Wii U spiking for a couple of weeks during the holiday rush). It may be more of a NOA centric thing to be honest. 

The hardware that actually carries over Nintendo's existing hardware philisophy of low power consumption/solid visuals/made-for-EAD chipset will be the handheld line, which I suspect will indeed allow for TV play eventually. It's just inevitable. 

It may even get them out of this Wii U mess a bit, if the next handheld can reuse or approximate Wii U engines ... Nintendo could move certain projects over or dual release them between their own platforms to be able to make up for their development cost.