Here’s a first pass of materials in Mental Ray. It’s a nice renderer, but the documentation is pretty bad. If I can make this look right, I’ll try and make a tutorial to get the look. One thing I can tell you so far: With chromed surfaces it’s very important to get the shape right. Something like a truck bumper is really just a steel stamping that leaves minute wrinkles and other manufacturing artifacts, particularly at the corners. You wouldn’t see it with most surfaces, but raytraced chrome will bring all your sins to light.