Unity 4.6 GUI Themes or Skins

I have not seen anything in the documentation, so I am asking here.

Is there a way to create a theme or skin in the new GUI? I would like to set things like button colors, background images and that sort of stuff in a theme so that changing the theme changes the whole GUI.

It would be nice if it also allowed more advanced things like positioning, but I know that is a lot to ask.

Just being able to select a color for backgrounds and text and then images for those kinds of things would go a long way.

There is no direct implementation of the legacy skins in UI.

The good new is this can all be replaced by prefabs.