PDO has announced that its TopSkin silicone cases for iPod nano (with video) and iPod touch, as well as its Aluminum V2 case for iPod classic and Aluminum N3 case for iPod nano, are now available. Previously announced, the TopSkin for iPod nano features a play-through design for Click Wheel access, as well as an open bottom for access to the headphone jack, hold switch, and Dock Connector. The sides of the case feature a “microtexture” pattern…