Some of the eBay stuff is made by the same companies that make the "brand X" wear. I wouldn't shy away from it so easily. Over the years, I've owned a few of the non name jackets and they have all been just as good as the average leather jacket.
To answer your question however, you would have to go to Kawasaki Parts to get an OEM Kawasaki or Ninja jacket.
17' Honda 1000RR SP - 08' Hypermotard 1100s
16' ZX10R - SOLD
14' Ducati Monster 1200S - SOLD
13' RSV4-R - SOLD
My ZX10R's 11' - 08' - 07' - 05' - 04' - ALL SOLD
Miss my Black 04' the most!
Never enough money, never enough time!