I've seen it in the last version of murrine, but only makes round the bottom corners of some menues (like in gnome-globalmenu). Hope that GTK allow to do that... It would be a kick-ass feature!

hey i will apply these and will see if it work , hope it work , it will of great benefit if it does, i need to apply roundness style on the corner of the menu item container. lets see what happens will post it after i try this out.