I havent noticed anyone out there changing the gui colors. Maybe because it's a little tricky editing the buttons? Well, here's my blue color scheme and modified buttons
color_inactiveborder 0.1 0.2 0.5 0.7
color_activeborder 0.2 0.5 0.9 1.0
color_inactivegizmo 0.1 0.4 1.0 0.7
color_activegizmo 0.1 0.4 1.0 0.7
color_clickgizmo 0.1 0.0 1.0 1.0
color_inactivetext 0.1 0.7 0.7 0.7
color_activetext 1.0 1.0 1.0 1.0
color_neutral 1.0 1.0 1.0 1.0
color_cmovement 0 0 0.8 0.5;
color_cattack 1 0 0 0.5
color_cretreat 1 0 0.5 0.5
color_cescort 0 1 0.5 0.5
color_cboard 0 1 0.5 0.5