Just thought I would pass this along... we found this ball at Toys R Us.
They are perfect for us because they are slightly oversized. He can get them in his mouth, but they are too big for him to get a good chomp on -- which translates as he hasn't popped them. And they bounce crazy high. He will snap at them as they bounce past and half the time that only makes them sail away from him, and then he goes after them.
It has made 2 ball VERY entertaining to watch. Sometimes, he goes up after them: