Mophie has debuted its new Juice Pack Air battery case for the fourth-generation iPod touch. Packing a 1,000 mAh rechargeable lithium polymer battery, the case offers up to 34 hours of additional audio or six hours of additional video playback, according to the company, and also features an integrated four LED battery status indicator, a standby/charging switch, a pass-through micro USB port for syncing and charging the touch while it’s…