One of the bombshells of Nintendo's E3 press conference was the word that Nintendo is working on Smash Bros. titles for both the 3DS and the Wii U. Sadly, that was all the information that we got, and it's likely all the info we will get for a while.
In the meantime, we can chew on this interview between Nintendo President Iwata-san and Smash Bros. creator Sakurai-san. It sounds like everything is in the planning stages at this point, but one thing is for sure, it sounds like Sakurai-san thinks it would be "wrong" to make a new Smash Bros. game that only adds improved graphics and a larger roster to the formula.
Some new ideas, like a more "individual" focused experience on the 3DS version where you may be able to customize your character, that would generally be "slightly different" from the "conventional" Smash Bros. games, are floated out there, while connectivity between the two versions is pretty much a lock.
Iwata asks about Smash Bros. [andriasang.com]
Other major topics that were discussed: