optimizing the class names of sprites

my approach in Sass

@import "compass";

$flags-spacing: 50px;
$flags-position: 50%;
$flags-sprite-base-class: ".flags li";

@import "flags/*.png";

$sprites: sprite-map("flags/*.png");

@each $sprite in sprite-names($sprites){
	.#{$sprite}{
		background-position: sprite-position($sprites, $sprite);
		height: image-height(sprite-file($sprites, $sprite));
		width: image-width(sprite-file($sprites, $sprite));
	}
}

result file

.flags li {
  background: url('../images/flags-s70f18acadb.png') no-repeat;
}

.argentina {
  background-position: 0 0;
  height: 14px;
  width: 14px;
}

.austria {
  background-position: 0 -27px;
  height: 15px;
  width: 15px;
}

.belgium {
  background-position: 0 -14px;
  height: 13px;
  width: 20px;
}

what i would have wanted

@import "compass";

$flags-spacing: 50px;
$flags-position: 50%;
$flags-sprite-base-class: ".flags li";

// something this property would be super useful:
$flags-sprite-prefix: ""; // to clear the standard "flags-" before every class name
// or change the prefix to something like "blah_" if so desired

@import "flags/*.png";
@include all-flags-sprites;