1) Navigate to Quicksilver's plug-ins folder:
~/Library/Application Support/Quicksilver/PlugIns/QS Flashlight Interface.qsplugin
2) Control-Click on the plug-in to show the package content
3) Go here -> Contents/Resources/ and there you'll see 2 .png files:
BarGradient.png and
BarGradientG.png
4) Mod away my young apprentice
