Note: APRIL FOOLS JOKE BELOW
Despite much speculation regarding what Squaresoft's GameCube title slated for year-end would be, no specifics were previously released about this mystery title. Many assumed that it would be the new series mentioned by Sakaguchi, Final Fantasy Unlimited. However, after Square's meeting with Sony executives, it had become increasingly clear that a new Final Fantasy title wouldn't see the light of day on a non-Sony platform any time soon. Other candidates were, of course, the rumored Chrono Break and SaGa Unlimited.
Square has put these assumptions to rest with the announcement of Seiken Densetsu: Revival of Mana. (Likely to be titled simply Revival of Mana in the states.) In a huge departure from the previous Mana games, Revival of Mana will take place in full 3D--albeit cel-shaded 3D. Given the series' history for multi-player action, it comes as no surprise that the game will support up to 4-player simultaneous action. It has yet to be confirmed if the previously mentioned "interaction with GBA" feature will end up in the package as well.
Two screens of the game's cel-shading engine in action have been released, although nothing else is known about the game. Given Nintendo's penchant for hiding details regarding upcoming games until the last-second, it is unlikely anything else will be known for quite some time.