You ever go to a golf course and see the ball cleaners they have? It's basically a tube with brushes in it and a piece with a hole for the ball that slides up and down, scrubbing the ball. That might be a cool idea for a ball cleaner.
You could just have a groove to store the balls in, maybe with a glass lid kind of like they keep the chips in at a casino.
As for other unique ideas for graphics, you coming up with them is what makes it unique.