Gnome on Ubuntu defaults to top menu
IIRC the patent/copyright infringement issue issue is that the menus on Macs drop down when you mouse over 'em, no click required. I believe they hammered Microsoft on that one circa Windows 2.0. . .
I'm not entirely convinced that that is an improvement anyway. In any case, any patents from the original Mac should be about to expire. Unfortunately, copyrights run a whole lot longer. (a century?)