If you're looking for a Kubota-branded striping kit, unfortunately you're out of luck. Kubota does not currently offer a striping kit as an accessory for any of its mowers. However, that doesn't mean you can't add stripes to your lawn with a Kubota mower – you'll just need to source a third-party kit and install it yourself.
There are a few different ways to go about this, but the basic idea is to add some sort of attachment to the back of your mower that will lay down stripes as you mow. This could be anything from a simple roller brush that paints lines as it goes to more complex setups with multiple nozzles that shoot out paint or even grass seed.
No matter which route you choose, the important thing is to make sure the attachment is properly secured and won't pose any safety hazards while in use. Once that's taken care of, all that's left is practice! With a little bit of trial and error, you should be able to get nice, even stripes on your lawn in no time.