After carrying my Hexar for a couple weeks on my honeymoon, the covering started to rub smooth:
The back got particularly bad.
So I ordered a Griptac kit from Cameraleather.com
Removing the covering of the Hexar was rather difficult, as the rubber material easily separated from its adhesive paper back. So I had to use a wooden tool to carefully scrape off the gummy paper from the camera. With the covering off the camera, it was clear that it's simply rubber, which explains why it rubs smooth so easily. The Griptac is synthetic, so hopefully it will last a while longer.
In the end, it looks pretty good!