According to a GamesMaster interview with Project Sora head Masahiro Sakurai (excerpted by ONM) 3DS flagship title Kid Icarus: Uprising might feature Kids Icarus, plural. "The online capabilities are currently being tested," Sakurai said. "There could be some versus play but we can't go into any detail. There are a lot of capabilities that expand on what was in the DS that people are taking advantage of."
If anyone's going to make a 3DS online game happen, it's Sakurai, one of the few Nintendo developers to make an online game (Super Smash Bros. Brawl). But how would a versus mode work in an on-rails shooter -- score competitions?