This time i will reply 6 months later, improvement
Can confirm that this does still work in 1.10.2 with a slight change, you are now required to implement IItemColor and then register it in the the post init on the client side only with:
Minecraft.getMinecraft().getItemColors().registerItemColorHandler(IItemColor , Item);
Im guessing some variation of this system will always remain in due to mob eggs using it, but again just a guess
if anyone ever actually reads this post and wants an example check out TheGreyGhost's example:
https://github.com/TheGreyGhost/MinecraftByExample/tree/master/src/main/java/minecraftbyexample/mbe11_item_variants