There's a company not far from me that does specialist coatings on metal.
I thought about a kind of rubberised coating (they do different colours), or they do granite chipping coatings by applying a resin base coat, then the granite (various shades). You can then leave it as it is or they'll build up the coat with resin so you've got a nice smoothe glassy surface. And a PC that will take 10 burglars to lift it through the window