Well it seems that HAL, the original developers behind Super Smash Bros and Smash Bros Melee will not be handling the Revolution sequel.
Though it won't be completely from a new staff as the original director as well as several core members of the team will be part of the development stuido. Apparently Nintendo has created a whole new studio to create Smash Bros Rev or atleast a new setting for them.
You can read here...
http://cube.ign.com/articles/673/673312p1.html