Cara Instalasi:
wget -O fakeosx.zip http://goo.gl/S3NLz
sudo unzip fakeosx.zip -d /usr/share/themes
gsettings set org.gnome.desktop.interface gtk-theme 'osx'
gconftool-2 --set --type string /apps/metacity/general/theme 'osx'
wget http://dl.dropbox.com/u/47950494/Mac-Lion-Icons.tar.gz
sudo tar -xzvf Mac-Lion-Icons.tar.gz -C /usr/share/icons
gsettings set org.gnome.desktop.interface icon-theme 'Mac-Lion-Icons'
Untuk docknya bisa pake AWN:
sudo apt-get install avant-window-navigator
Sumber: http://www.upubuntu.com/2012/02/fakeosx-another-mac-os-x-theme-for.html