I had an implementation where I needed to take this technique a step farther, and wanted to outline my work. The below code does the same thing but uses SASS, Bourbon, and an image sprite.
@mixin sprite($position){
@include background(url('image.png') no-repeat ($position), linear-gradient(#color1, #color2));
}
a.button-1{
@include sprite(0 0);
}
a.button-2{
@include sprite (0 -20px);
}
a.button-2{
@include sprite (0 -40px);
}
SASS and Bourbon take care of the cross browser code, and now all I have to declare is the sprite position per button. It is easy to extend this principal for the buttons active and hover states.