Nintendo DS/WMG

The i in DSi represents an imaginary number.

 * Obviously, because the DSi is much more complex than its predecessors.
 * i is the square root of -1. The negative of a tangible matter object would be antimatter. So, if you were to fuse together two DSis properly (so that the processing powers multiply, instead of add), you would produce an antimatter DS.
 * Furthermore, fusing a DSi and a normal DS together produces a gaming supercomputer and single extra unit of waste matter. This can be proven as follows: a normal DS can be represented as (DS - i), as in, a DS without the i. And a DSi is (DS + i), or a DS with an i, which happen to be complex conjugates of each other. Fuse them together, and you get DS^2 + 1.
 * So wait, would it print anti-money?
 * No, thats what the PS3 does.
 * Zing!

The D Si is a cruel jab at people who don't have gamer friends or family with which to play Wii games.
Wii do not want to play! Also, they want your DS to be stolen ("D Si want it! Give!")

Shiggy's DS does print money.
Nintendo can do anything. Remember that their hardware is indestructable.
 * Heck, the original Game Boy did have an actual printer accessory.

DS stands for "Drug Smoking"
And Wii is a Japanese misspelling of "weed" minus the D. What Do You Mean It Wasn't Made on Drugs??
 * Given Nintendo's existing track record with drug themes, it's somewhat plausible.

The DS phat's shoddy hinge was the result of Nintendo putting too much of their Nintendium into Wii production
More specifically, someone forgot to Carry the One or Misplaced a Decimal Point, and got too much Nintendium put into Wii production, and not enough into the DS phat's production. The result? Rather than an indestructible console and handheld, we got a mostly-indestructible handheld, and a console that was so indestructible, it started destroying other things.
 * Whatever the problem was, they magnified it for the DS Lite rather than solve it. Maybe somebody in R&D was trying to weaponize Nintendium?
 * In any case, the simplest answer is probably that the Hinge Nintendium was redirected to the Wiimotes due to a lack of sufficient supplies for both, with the Wiimote being a higher priority. By the time of the D Si, they managed to get enough stockpiled that they could fully supply both lines.

There will be a DSi netbook.
Just like the DSi XL, only larger but thinner; just like a netbook, only game-centric and with a touchscreen instead of a keyboard.

If this ever gets made, then Nintendo will either take over the electronics industry or self-destruct.