You may have seen a few concepts already for a notification centre for Windows Phone. The two main concepts that work with the Windows Phone UI utilise either a swipe to the left (thus three homescreen view) or volume control buttons as opposed to pull down notification in other OSes.
This one on TheVerge forums uses the volume control option. The notification look like your notification in the people hub/Me tile. The volume control option is accessible throughout the whole UI, more so than a swipe from the main screen. That’s what I love about the music controls. Ideally perhaps there might be some other shortcut controls?