Varusteleka has this coat/cape piece on their website that looks verrrryyy interesting. Can be purchased insulated or non insulated. Claims to be water and windproof and can be worn as a cape, coat or sleeping bag-good for you cold weather types. A bit pricy but man if it was well built and long lasting might be worth it.
Särmä TST Thermal Cloak
This multi-functional thermal cloak can be used as a cloak, sleeping bag and emergency shelter even in extreme weather. Fast international delivery!
www.varusteleka.com