Nintendo will release their fusion project. This won't be a hybrid, as many suggest. I believe there will be a hybrid console at some point, but the tech right now is too far away for that. What we are going to get though, is a set of TV Console/Handheld which will be able to run the same cartridges.
I believe that around the 2017/18 timeframe, Nintendo will release both the Wii U and the 3DS succesor in the form of this fusion. The "dock" part, will be based on the new ARM v8 SoC AMD will produce on 16nmFF+ tech, with a beefed up gpu and a shrinked Wii U cpu for backwards compatibility. The handheld part will be based on the same SoC family, but it will use obviously a low powered variant of AMD's SoC. Probably A72 or A57 for the console vs A53 for the handheld. With a lower powered gpu and lower RAM. I believe the handheld will have one HD touchscreen, and will be able to function like the Wii U gamepad if connected to the console. Same inputs as the New 3DS (probably a better c-stick) and the 3D stays. It will be backwards compatible with 3DS only, DS will be dropped.
The game library will be common for both parts. They will use the same OS, the same CPU family, and the same Eshops and Game cartridges. Cartridges for the 3DS top at 8gb, i believe the fusion ones will have also 16,32, and even 64gb roms, just in case. This is plenty of room for PS4+ level games. Games for this fusion family will be the same, just with 2 sets of graphical settings, one for the dock and one for the handheld. Nintendo will be able to release their games far more frequently and avoid having to rely on third party during their draughts.
AMD has already announced they have 2 design wins for their SoCs. Rumours have spread around that Nintendo and AMD will cooperate for their next consoles. Nintendo has been using AMD gpus for a long time, for three console generations in fact. AMD will enter the ARM SoC market soon. Nintendo has been using ARM cpus on their handhelds since the GBA. With the 64 bit ARM processors on 20nm and 16nm, for the first time ARM processors will be able to compete with low power laptop/desktop processors. They will be competitive with ARM's Jaguar that powers next gen consoles... They will be able to run the same code with the smartphone chips... Does it make sense now?
Nintendo will be able to use the ARM cpus they already have experience with, with the AMD gpus they already have experience with, will be able to run the same code on both console form factors and handheld form factors, and cartridges will have plenty of space, actually more than bluray, in current prices, but with far better read speed... Nintendo loves cartridges on their consoles... Do the math...
PS: Backwards compatibily is possible on one single HD 3D touch screen. Just show both screens either side by side or top down. Problem solved. I believe the next handheld will have the Wii U gamepad form factor...