At Ubisoft Reflections currently working on Watch Dogs, they've got an unannounced title they're currently working on as of a statement at Joystiq
"We work on [Just Dance 4], and we work on something that I'm not supposed to tell you about. I wish that I could. It's going to be announced at E3." - Pauline Jacquey, Managing Director at Ubisoft Reflections
There isn't any information floating around on it yet, but as the quote states, we'll know when E3 comes around on June 11th to 13th. Rumors are that it'll be a racing title, but until we nail down what it is, we'll keep you guys in the loop whether it's a shooter or not.