-take a look at the .tabBar css class. it has position:fixed, top:0 and left:0, and this is why the tabbar is still rendered on top, even though its parent is somewhere else - fixed is relative to the browser...
-There is an open bug on this.
-you could try and play around with the position property of tabbar (or his parent) to change this - just make sure that it doesn't affect the elements above/below the tabBar.
-In addition - the Android tabbar is supposed to be at the top/bottom, according to their design principles. so maybe there is a better building block for your needs?
cheers