Once you create an iDVD project, go to the "tree" viewer. You'll see a box on the leftmost side for automatic play. All of the flowcharts that leads to the menus, movies, titles etc start from that box. Normally it is black, as there is nothing on it, but if you drop your movie file on it, it will create a DVD that plays automatically. It is designed to display previews before the disc menu come on, but you could use it for your purpose and just skip menus all together. However, I don't remember whether there was a time limit on that box.