@Adam
Good article on this, old link that can help with this, http://wpengineer.com/475/top-level-menu-in-wordpress-27/
Also, the soluion that @Norcross is proposing works great, but the icon 99 will throw an error, you could leave it blank, eg. '' instead of 99. You could also have your own custom icon using basename(__FILE__) and the filename.