Try this out and see if it works for you. BB-Skin-Large-Color-on-Black.zip
The skin includes the PSD templates you can open with GIMP
The PANELS folder in the color behind the icons you can change them to whatever color you like also set the Black layer in the PSD to that same color.
Copy the Skins folder "Large Color on Black" to bb\Data\CustomSkins
Copy the Large Color on Black.csc to bb\Data\Schemes
(In older BB
Rename C:\bb\Data\Images\MainScreenButtons\ > MainScreenButtons - Gray
Extract the folder Large Color on Black and Rename > MainScreenButtons)
right click the chord sheet > Display Options (or Options > Preferences > Display)
Choose Skin > Large Color on Black
Load Scheme > Large Color on Black
If you don't choose the Large Color on Black Scheme and want to keep the white chord sheet in Display Options
up the top left choose Mixer Font and set it to a color other than black.
EDIT: the Mixer Font isn't saving in the Scheme at the moment so you will need to change in manually.