Make Maps block color id changeable with Texture pack.

A change i would like to see is to make the color of block on a map changeable. For exemple, if i want to make it so that dirt blocks appear purple on any map, i would be able to by using a texture pack. Similarly, before a certain update, weat didn't appear yellow on maps but green, i would have been able to fix it myself with a texture pack rather than wait for an update.