Avalon with vector based UI?

Seems that the graphics engine of the future Longhorn OS from Microsoft might support vector based UI elements. It's about time! Current bitmapped UIs work fine on screen with similar DPI, but the more we see really highres screens, especially on mobile devices, a resolution independent UI is a must. Apples MacOSX graphics engine called Quartz uses PDF and could be resoltution independent, but all the UI elements are still bitmapped and right now there is no official way to change the DPI in MacOSX.