Here is my first milestone. Adding the tabs.
The tabs highlight when tracking over them and the selected one has the bold appearance that you see. I used Paint Shop Prop to take screen dumps of Office 2007 Excel and work out the correct color values to use for each of the three color schemes.
Notice how the black scheme uses a different way of painting the tracking tab. It has a more glassy feel than either blue or silver. Takes extra time to duplicate both of the drawing techniques but it is worth the effort to try and get the Krypton version as close as possible to the original.