What makes you think you want or need one?
Have you wondered why you can’t find one? Assuming you’ve looked, that is?
One of the 1600’s many redeeming features is that you don’t have to waste money adding things to it. That includes ridiculous crash bars for the panniers, little winglets, bolt-on exhausts, high level brake lights, extra lights at the front or any of the other shite that bods add to the bikes, just in case 320 kg isn’t quite enough.