I,ve already deleted that image as the buttons were too much of a problem.
Its pretty straight forward though.If you look at the last post in the theme guide on margins,the same applys to a vertical taskbar. It would be a vertical gradient for example that would distort.Its just a matter of holding the left,right , top and bottom firm with sizing margins ,this leaves the solid color in the middle(for the image in the pic I posted anyway) to do all the stretching.