I could see Nintendo releasing a new, revised version of Wii U, one that uses a System-on-Chip, rather than a Multi-Chip-Module.
A SOC would reduce manufacturing costs because it's literally one chip with all the processing tech in and using one reduces multiple stages of making each system, it could even allow Nintendo to reduce power consumption by going to a 28nm manufacturing process, which instantly would reduce TDP, so they could definitely shrink the size of the box further.
Making a new chip they could even include 3DS processing technology into the die, allowing the new model of Wii U to play 3DS games without emulation.
Costs could very likely be reduced to allow this system to hit that kind of price point.
I can see NX being a new Philosophy with a Wii U/3DS hybrid console being how they launch it.
If this is what NX starts out as being, it could very well be announced at E3 2016 and release in the holidays.
Nintendo could then include all of that tech into their true 9th generation system, just with another core 9th gen SOC, but the overall system adds that very same Wii U/3DS SOC onto the motherboard of a system capable of running next gen multiplats and higher end Nintendo games.
As the 9th gen rolls around the more powerful model could be released.
