Smash Brothers Report: Developers considering downloadable content

Relevant passage: "It’s worth noting that the Smash Bros. franchise may not see additional characters, but I think the door can’t quite be shut yet. For Super Smash Bros. Melee, the developers included trophies in the game that could only be accessed by playing other games that came out later – such as Pikmin and Animal Crossing. I like to think that Nintendo could do something similar with the newest entry, but actually add full characters instead of just pre-made trophies. When the new Zelda comes out, perhaps a character from the game could be added as DLC if users pre-order the game or perhaps Waluigi could be available to those who purchase a new Mario Tennis or Wario game."