With most smartphones having HD resolutions, I think by 2016 it would be affordable for Nintendo to release a $200 handheld with a pixel density comparable to today's mid-upper end smartphones. That is all that's necessary. If you are talking about graphical fidelity, expect somewhere between the PS3 and Wii U, with certain advanced features introduced by architecture innovations. To be honest though, I feel that with the 3DS and especially Vita, handhelds have peaked in the cost-benefit of more powerful hardware. We'll likely see money put into more expensive screens (anti-glared), textured touch screens, etc, etc.

no. I don't even have HD,to cheap. lol

HDS would be a strange name, but I'd expect announcement in 2 and a half years, at e3 2016, with release either late 2016 or early 2017. Unless they pull another GBA and kill off the 3DS sooner than later. O_o

Hardware-wise, I think they may be able to use Wii U as a baseline considering how it already uses so little wattage. Put in 2GB RAM, a pair of 1280x720 screens, 3.5 - 4.0 inch screens. It will look pretty nice with a small screen at that resolution. It'll probably have some graphical effects newer than Wii U / PS4 / XB1 due to technological advances these next two years will probably have, similar to how 3DS although less "powerful" than Wii, it has a more modern GPU with neat graphical effects that look very nice. Obviously it won't reach polygon counts at Wii U's level, but it'll be close, and a good little handheld. 

The 3DSXL is great as of now and doesn't need replacement. I don't want another model.

I'm hoping a new Nintendo HH is released in Early 2016. That gives it 4 full years on the market. (2012, 2013, 2014, 2015)

Tech is moving pretty quickly. Plus, I won't buy one until later down the road meaning sometime in 2017. I would like it to have a good line-up by that time.

Bold and randomish prediction. Nintendo's next system will be shown off at E3 2015 (just over a year from now!).

Dual screen is over I think. Nintendo will be going single screen next time out, the 2DS which is really a single screen and the Wii U tablet design pretty much foreshadow it.