It would be extremely odd to see Nintendo with the most powerful home platform, if it turns out to be that way.
I don't think a summer release, which people seem to be leaning to, is likely at least, for North America and Europe. The fact that this platform was not mentioned in forecasts for this financial year completely rules out any chance of release before spring 2012 (as predicted, against a disgruntled few members), and I just can't see them launching before ~October 2012. Summer is a real down-time for home platforms, and could kill the sales hype they crafted with Wii.
I can see this launching at the beginning of October 2012, and getting close to selling out. With Thanksgiving, they will receive a boost of momentum, which will ensure all stores are completely and absolutely sold out. A large, well-timed shipment in December will boost sales further, and hopefully carry the momentum/"must buy if seen on shelf" mentality through into 2013.
I can also see it launching for $299. They will have learned that $250 was too much of a step-up from the launch price of the DS, so will not launch this home platform for more than $300 (up slightly from the Wii's $250). They will not launch at $250, as that would de-value the 3DS and have consumers question the quality of the build (Marketing 101). There needs to be space of $50 - 100 between the two to justify purchases of both platforms to consumers.