After seeing Oda actually gave Chopper his own Jolly Roger apart from Hiruluk's (as seen in this color spread: [link]), I was surprised there was barely a peep about it. So I tried my hand at a full-sized replica to join the rest of the crew's.
The only part I had to take liberties with was what was covered by Chopper's arms; couldn't tell if it was antlers or more sakura petals, so I decided to mirror Hiruluk's flag with 4 petals there and here. Use this however you wish, but credit would be nice!