I've been using this for the last couple of weeks.
http://simplism.jp/en/products/iphone/flip_note_style_1/index.html
Overall it works well. Being made for Japanese, it opens backwards, but that's a big plus as it allows the volume and mute buttons to remain available for use when closed. Unlike some similar cases it adds little bulk. Unfortunately in execution the materials look rather cheap.
I'm still waiting for somebody like Master Piece or Valextra to make a high quality leather shell for the iPhone 5.