With a design that looks at least slightly inspired by Stanley Kubrick's 2001: A Space Odyssey, SwitchEasy's Odyssey for iPhone 4 ($30) is the company's latest multi-piece case, and a real stunner. The Odyssey features an inner soft plastic casing, an interchangeable back panel -- two of which come with every case, differing in color -- and a hard plastic outer frame. Button coverage is significant and well-designed. In addition, the Odyssey benefits…