In regards to a new game plus file, no. I’ve finished Star Ocea 3 a few times now, and there is no game plus file (Starting a new game with all items and such.). Even with games with the game plus feature (I’m using Suikoden IV as an example… but I strongly urge people to avoid this game.), like Suikoden IV, have it that you finish the game, and then have the game plus file. What that does, is give you all your items and money from the previous game. If does not give you, the levels you built up.
In the sequel, Champions: Return to Arms, you can also import your characters from Norrath. If you like the occaisional hack-and-slash collecting RPG, Champions is worth a look.