Uh, where have people read that retail carts are region-locked? Nintendo has never region locked any of their handheld systems. I can see it being region-locked for the digitally distributed titles, but that's about it.
Fishin, only downloaded games will be exclusive as far as I can tell. Or games that use the camera. Inside it should still be the same as the DS and DS Lite.
$180 is the price you can find the Xbox 360 Arcade at any given month. I'm sorry, but unless they suddenly announce a Zelda game that's only available on the download service, I'll be sticking with my DS Lite.