Unfortunately, Sega isn’t working on Super Monkey Shinobi. The monkey ninja bit is a mini-game which the ESRB description leaked.
In one mini-game, players become "monkey ninjas" and must step on floorboards to block ninja stars and "cartoony" smoke bombs: When monkeys are hit by a ninja star, there is crashing noise and a red mark that appears on the screen; when monkeys are hit by a smoke bomb, a plume of smoke appears and fills up the screen momentarily.
On second though, Sega should add a simian version of Joe Musashi (Joe Monkashi?) just for this mini-game.
Super Monkey Ball Step & Roll will be in North American stores on February 9, 2010.