It won't cost much more than DSi XL. I'm expecting it to be around $200, could possibly be up to $225 or as low as $180. Remember that people were bitching that DSi and DSiXL were overpriced, and the reason is Nintendo can afford massive margins on those. However with a new platform it has to quickly get to a price that's reasonable, so they'll have much lower margins initially (but still profitable per unit).
A game I'm developing with some friends:
www.xnagg.com/zombieasteroids/publish.htm
It is largely a technical exercise but feedback is appreciated.