The next RPG coming from Mistwalker (founded by Final Fantasy creator Hironobu Sakaguchi) is The Last Story, exclusively for the Nintendo Wii.
Details are scarce but this game is a joint project between Mistwalker and Nintendo.
The Last Story logo somehow resembles some past Final Fantasy logos
Concept art for the game
So why is this game a Wii-exclusive? My theories...
1. Mistwalker was probably tired of waiting for projects from Microsoft Game Studios, so in order to keep themselves alive financially, they went (or got approached by) to Nintendo
2. Lost Odyssey and Blue Dragon just did not sell enough worldwide on the 360