You could also Sugru the knees of some of his pants. *g*

www.sugru.com (air-curing silicon rubber that bonds to nearly everything and is washer-safe, etc.)

ETA: re: Santa... we totally did the Santa thing to some degree. We just explained later that Santa was the embodiment of a great idea and that we put "from Santa" on gifts when we wanted to be anonymous about who was giving it.