This sort of flew under our radar, but with the launch of Kirby: Battle Royale in the Americas, the Mirror Kirby 3DS home menu theme has been silently made available to download, for no cost whatsoever! Definitely pick it up, it's very cute and plays the Marshmallow Castle theme from Super Star!
On a related note, the winner of the second Copy Ability Poll hasn't been revealed yet, but it's only a matter of time until we find out which new ability will be added to the roster of Battle Royale. Which one are you hoping will win?