One of my favorite cases for my iPhone 4 is made of aluminum and has a machined look to it. A company called LTD Tools has cases that are also made from metal. The cases are made from metal and are offered in styles with flip up lids that protect the screen. The case also wraps around the device to protect the whole smartphone or tablet.
These are not cheap cases. The iPad 2 case sells for $140 and will ship starting on May 28. The iPhone 4 case is offered in two styles. One has is called the 180 iPhone 4 case and sell for $45 and ships June 1. The other is the 360 iPhone 4 case and sells for $75 with shipping set for May 28.
The iPad case comes in four colors including charcoal, light gray, yellow/light gray, and blue/light gray. The 360 case is offered in brushed stainless sonly and the 180 comes in brushed stainless or gold stainless.