Murrine

GtkScrollbar::trough-side-details = 1

If you set that for your scrollbar widgets, you can then theme the trough. Beware as this messes up rounded scrollbars.

Below is my scrollbar config section:

style "scrollbar" {
GtkScrollbar::trough-side-details = 1
GtkRange::trough-border = 0
GtkRange::trough-under-steppers = 0 bg[SELECTED] = "#111"
bg[SELECTED] = @selected_bg_color
bg[SELECTED] = shade(1.20, @bg_color) bg[NORMAL] = shade(0.80, @bg_color)
bg[PRELIGHT] = shade(1.20, @bg_color)
bg[ACTIVE] = shade(0.80, @bg_color) fg[INSENSITIVE] = shade(0.85, @bg_color)
fg[NORMAL] = shade(0.50, @bg_color)
fg[PRELIGHT] = shade(1.50, @bg_color)
fg[ACTIVE] = shade(0.85, @bg_color)

engine "murrine" {
roundness = 0
contrast = 0.5
}
}