Nodge

@sprite1: 100px;
@sprite2: 200px;

.data-sprite(@filename) when (@filename = sprite1) {
  background: red;
}

.data-sprite(@filename) when (@filename = sprite2) {
  background: green;
}

.sprite-width(@width) {
  width: @width;
}

.sprite-height(@width) {
  height: @width;
}

.bg-icon(@filename) {
  .data-sprite(@filename);
  background-repeat: no-repeat;
  .sprite-width(@@filename);
  .sprite-height(@@filename);
}

html {
  .bg-icon(sprite1);
}

body {
  .bg-icon(sprite2);
}