You guys!
They are making a Professor Layton/Phoenix Wright crossover!
It is like they went "Hey, how can we make the most awesome game for Kate ever?"
And then they went, "Well, 'Rock Band: Final Fantasy' probably has too much licensing involved. So let's do Professor Layton and Phoenix Wright."
*flails with joy*
Some googling reveals
the Japanese teaser site, which, well, is a logo mashup right now. But it hopefully means it's not some sort of elaborate prank!
Squee!