Marware has introduced several new cases for the fifth-generation iPod nano and second- and third-generation iPod touch. The MicroShell for iPod touch 2G and 3G is a thin, half-shell hard case offering a thickness of less than 1mm, a metallic finish with a rubberized feel, open access to all ports and controls, and an included screen protector and cleaning cloth. It is available now in six colors and sells for $25. The EcoSleeve for iPod nano 5G is…