Two new DLO silicone rubber cases have been released for the iPod nano and iPod touch, both under the Jam Jacket name, but each with a distinctive design. The iPod nano version is called Jam Jacket Design ($20), and differs from the original third-generation iPod nano Jam Jacket in rear "etching" and comparatively unadorned front and sides. Seemingly made from opaque black-inked rubber, the ink is either not applied or removed on parts of the case's…