awesome. try boffer. u make a mold and pour in liquid boffer foam which u can purchase, put in a dowel, then do it again, put the dowel in between them and glue them together, then u can hit without it breaking.
Scaling it up is possible, but it would take re-configuring the entire template into smaller pieces so that they would fit on sheets of cardstock for printing (I don't have time to do that myself). Another problem is I doubt the handle would be strong enough at a larger scale.