FrostByte
Smash Lord
I'm not on the RPG part, but I could see it working as MMO. You change features (such as colour) of existing characters to get your own unique one. Then you go out into the Smash Overworld where you can meet people and play them in matches or you could get people to walk with you to stages like pokemon stadium or the figure 8 racetrack. Give everyone a set of phrases they can use, like "battle?" or names of stages. That'd be the best way to use Nintendo's online service to the fullest, since they're so hellbent on ignoring communication.