I agree with you, I'd be nice to see it happen, yet I am doubtful that it will. I know there are a few tails that allow the tip to be coloured differently (by again, using the hair's highlight colour). It's not exactly what you may be after, but it's something, I suppose.

Other than that I can't really think of anything else that could achieve such a thing, at least not with what we currently have. Let's hope they release some hairstyles in the future with a different colour pattern on the ears, as that may be the best thing they could (hopefully) do for now.