Sadly, SF643D will not be a launch title, instead launching in mid-to-late 2011 in Japan, meaning likely late 2011-to-early 2012 US.
On the bright side, we get to see the new Landmaster:
Miyamoto also hinted at the possibility of new content in the game, but there were no elaborations.
Hopefully we will get some news soon on the US 3DS hardware launch. GameStop is already taking pre-orders, and NCL says March, but until NOA says something, we are in the dark with March only about two months away.