This is one very cool article in which Phil Middlemiss explains how to simulate backlighting on a selected list box item.
The challenging bit was getting the selected item in the list box to cast a glow on the things around it. The glow seems to escape the list box itself. The reason this wasn't straight forward is that the ListBox control clips its content to keep everything inside the scrollable area. My first instinct was just to set negative margins on something inside the ListBoxItem's template (ItemContainerStyle), but that's when it became obvious that it was being clipped.