It's been a long time since you wrote this but every now and then people look this up in the searches and find no answer. This is unfortunate as this question should of been answered regardless if you have it now.
Cut and paste this for your searches
Kawasaki ZX6R 636 05-06 Top Saddlery Gas Tank Cover
Replace the year with your year
They look like this, made out of leather, a bit pricey and straight from france