如何在Objective-C中自定义绘制窗口标题栏？

I'd like to customize the way I draw the window title bar on OS X. Specifically, I'd like to do something like the Twitterrific app where there is a custom close button, no min/max buttons, and the window title text is right-justified. Unlike Twitterrific, I'm not looking to custom draw the entire window (though I'm not completely opposed to that either).I'd like to customize the way I draw the window