While Skinit and GelaSkins both offer countless printed vinyl skins (some with matching wallpapers) to protect and personalize the HTC EVO 4G, the graphics are flat and mass-produced. Wouldn't you rather have something with a light-reflective texture individually made by hand, either by you or the person whose handiwork you see here?
For $20, xda-developers forum member Hrshycro will apply a carbon fiber film—cutting and heat shrinking everything by hand—to your battery cover "as quickly as possible." Alternatively, you can buy the film for $8 from the appropriately named CarbonFiberFilm.com in your choice of color (silver, white, graphite/gunmetal, black, light pewter, dark pewter, brown) and follow Hrshycro's tutorial to do it yourself.
The vinyl skin is water-resistant, self-adhesive, and is made to definitely outlast your EVO with its 12-year indoor lifespan. There's no guarantee that it can be removed without any ill effects, though, so make sure you really want to do this to your phone if you don't have an extra battery cover on hand.