The first smart phone I ever got was a MyTouch 4G. I still use it today, and I don't know how I survived without a smart phone at all. When it came to customizing it though, I found that it was damn near impossible to find a case for it. There are so many different styles of Android phones that making cases for all of them would be incredibly difficult. That's one aspect that makes me insanely jealous that I don't own an iPhone. Take these retro gaming cases from Martin Millar. They're fantastic!
You've got Impossible Mission from the Commodore 64, the classic arcade shooter Raiden, Roadfighter, and a dozen other games that I wasn't alive to even see. If you like them enough, you can even purchase them on RedBubble.