FS: Feathered Friends Rock Wren wearable sleeping bag. From the FF website:

The zippered arm holes of the Wren series allow you to essentially wear your bag like an uber-warm parka when you're perched 10 pitches up, while the two-way center zip provides a convenient opening to remain tied in while you sleep. Trips out of the tent in the wee hours of the morning are no longer a matter of necessity overcoming endurance; the Wren's drawcord bottom the bag can be opened up and easily slipped above the waist.

The latest Rock Wren Nano is $339; mine is the older version. Price is $160 plus shipping, Paypal gift.