More control over entity textures

I've always found it weird that you could control so many aspects of Minecraft's mobs with commands (you can make certain zombies have custom loot tables, for Pete's sake!), but you could never actually change their textures in the same way. All creepers have to have the same texture, and the same goes for every other mob in the game. I propose adding a field in any command relating to mob data called CustomTexture, which would allow you to specify a certain texture file for your mob to pull from.

For example, if you wanted to summon a Red Creeper variant of your average creeper, you'd create a resource pack, plop your new creeper texture in there, and then run the command: /summon creeper ~ ~ ~ {CustomTexture:"textures/entity/red_creeper.png"}. Note: If the game cannot locate the file you call for, it will resort to the mob's default texture.

This would make custom mob variants much more distinguishable, and I know plenty of map-makers have been waiting for a feature like this for a very long time.