This tool sounds amazing:
Maybe a future feature for Elive? 
I've seen it mentioned but never looked it up.
Expecting it to be GTK/Gnome (xdg) oriented it might be nice for E16 but also might have unintended side effects with some color schemes.
Silly stuff like that, in general the bottom of a wallpaper is darker thus making sense to have lighter shade icons on a transparent panel/bar.