If you live in North America and you're hoping you get your hands on a Nintendo 3DS Circle Pad Pro accessory in order to play a few games that would perform better with a second slide pad, then you'll have to drive by Target and Walmart in order to stop in at GameStop.  Nintendo of America has announced that the peripheral is an GameStop exclusive in North America.  Here's a bit of the press release:

Nintendo is also introducing an optional accessory that gives Nintendo 3DS owners a second analog stick to control compatible games. The Circle Pad Pro will launch in the United States on Feb. 7. It will be sold through GameStop stores and online at http://www.gamestop.com at a suggested retail price of $19.99. The Circle Pad Pro is a comfortable cradle that holds the Nintendo 3DS system while adding an analog Circle Pad on the system's right side. The attachment also adds additional shoulder buttons to give it a feel more akin to traditional console controllers. It is designed as an optional accessory and is compatible with Resident Evil: Revelations and Metal Gear Solid 3D Snake Eater.

This isn't the first recent Nintendo product to be offered exclusively at GameStop.  The long-demanded Xenoblade Chronicles for the Wii is headed to North American GameStops next year as well.  The message that I'm taking away from this is that, like Xenoblade, Nintendo's American arm doesn't expect the Circle Pad Pro to be in high demand outside of the core gaming market, so there's no need to spend the money and time getting it into stores everywhere.  If a majority of 3DS owners don't own a Circle Pad Pro, then what's the incentive for publishers to release games that support it?  As for me, I'm not against buying a Circle Pad Pro if a game that I really want to play would perform significantly better with the add-on. Resident Evil and Metal Gear Solid aren't my thing, so I'm going to hold off for now.  Aftermarket add-ons like this rarely succeed in large numbers (especially if they're hidden away at only one retailer).  Why, if Nintendo hopes to make the second pad a standard, then they'll have to release a new model of 3DS with the extra controls built into the unit, and that would be downright nutty.