Actually, there is a program for the Gnome panel called Global Menu that emulates the Mac Menu perfectly by moving the menu options from the window itself to the panel.  Currently it doesn't work with Firefox (and of course Songbird, since they share common code) or OpenOffice, but for everything else it's a pretty sweet deal.  Also, the first time I tried Mac4Lin, I used a .sh script.  Granted, that was from a different website.  But it worked perfectly.