I believe this game will never come to the western shores on PS3. Like pretty much all jrpg that were released as a timed exclusive, we have yet to see a western release on any of them. Eternal Sonata will not make it here on PS3.
Maybe japanese developers will earn a lot of money by accepting the money from Microsoft but by doing so, they are alienating themselves from their consumer over there.
How many cups of darkness have I drank over the years? Even I don't know...