if you willing to stump up the cash (£120ish) I'd look at Outdoor Designs Alpine Bivi. It made ofthe new highly breatherable GoreTex and is designed to be fully enclosing & therefore element proof. Also very warm - it'll add another season if fully closed and light. The zip can be left open as there is a small mossie net at the enterance (3" or so wide).
For info check out the below, but most climbing places sell them & often cheaper:
http://www.fieldandtrek.com/ft1/cat...&mscssid=09CHVUKEWEW09MECTEGUHU2HTFLE05J5
For info check out the below, but most climbing places sell them & often cheaper:
http://www.fieldandtrek.com/ft1/cat...&mscssid=09CHVUKEWEW09MECTEGUHU2HTFLE05J5