Last time that I checked, the limit was for 50 files open at once.
But I'm not sure that separating your tables into different files actually simplifies the sync process. Whether all in one file or in separate files, the data in the tables still have to be correctly "synched" and this can be a potentially complex process.
Both 360Works and SeedCode offer tools for synching FileMaker databases, so you may want to look them up on the web and see what they currently have to offer in this area.
And this can be an unnecessary thing if you can host the database from a single system and connect all of your devices to it as clients of that hosted system.