Nintendo has enjoyed nearly two decades of portable gaming success with the Game Boy line of devices, more recently printing money by way of the touchscreen-equipped Nintendo DS and DS Lite.
Sony has been able to achieve a good level of success with the PSP and PSP Slim. While devices like the Sega Game Gear and Neo Geo Pocket have come and gone, their full-sized home counterparts have also come and gone.
For all intents and purposes, the Microsoft Xbox 360 is still doing very well in the marketplace. People are still more than happy to enjoy games like Halo 3 and Rock Band on the Xbox 360, so it's clear that Microsoft has a formidable game-playing following. Why is it, then, that Microsoft has yet to grace us with any sort of portable gaming ambitions? Where is the Xbox Portable?