Yes, Sly Cooper will be coming out fall 2011. A guy from Sucker Punch said "Sly Cooper 4 will be the best game of its series. The main character of this game will be Bentley and Murray and Sly. They will travel in time seeking his ancestor's."
there is 4 games of the sly cooper franchise.3 of them are ps2,and sly cooper 4 is going to be for the ps3,coming out in 2012,this awnswer was made in november 2011.but after sly cooper 4 there MAYBE will be more.