All4Cellular offers the SaFPWR Milano Rechargeable Smart Battery Case for iPhone 4 and 4S in Shiraz Red Crocodile (pictured) or Black Lizard for $54.95. Coupon code "A4C10" cuts it to $49.45. With free shipping, that's $24 under our spring mention and the best price we've seen. This case purports to double the battery life for an iPhone 4 or 4S. Deal ends November 13. Update: The price has since dropped to $49.45 before coupon, $44.95 after.
It's also available in Smooth Black for $53.95 with free shipping after the above coupon. Update: The price has since dropped to $54.95 before coupon, $49.45 after.