That's kind of the point of this thread. Using $foo window manager, and $bar theme, and adjusting the prefs/widgets like $so, it is kind of like a Mac.
I just set up Xubuntu (Ubuntu Linux with Xfce desktop) with its Platinum theme, which puts the window widgets in the correct locations for you. In the Appearance control I set the desktop to use a light theme with a similar shade of gray - since classic Mac OS didn't have a task bar sort of deal, that's the best I could do. I have the Virtue font installed, so I use that for the window manager (title bar) and theme (menus) font. By default it's focus/raise-on-click. Not too bad, from an appearance standpoint.