I have been thinking about trying to get Bob J Gear to make one of their heavy silicone bumper cases like I have for my Asus Vivotab Note 8.
Perhaps if we started a thread on petitioning them they might.
They pop on and off easily even with the bumper thickness, and we probably wouldn't want cutouts for the ports. We might want a grommeted hole in the center of the top to clip a float to if boating or if reading in an inner tube at the lake. The hole would also let you hang the Kobo on a cup hook or nail.