with the blanket topic.. a lot of guys in the *ultralightweight* groups I'm in use a duvet. Same sort of principle as the Rab Top Bag, whats the point of the down underneath the bag, when the warmth relys on the loftyness of the down of the bag, its insulation. Sooo The Rab Top Bag does just that.. it has no down underneath where it will be bottomed out, only down on top. So some guys have made down duvets.. PHD will make you one.. or ideally get some pertex and the spare duvet out of the guest room and make your own! You could even use silk on one side to lower the weight still more, but if you sweat loads you might be a bit cold the next night if you dont air it properly. Primaloft is a great alternative for the damp UK!. You can also buy in fabric shops by the meter very cheaply! I use 4oz primaloft for making quilts ie quilting! But it is avaliable up to 30oz which is arctic stuff. I personally use a PHD down bag and a have two Rab down bags, I always use a silk liner too. I have a pertex outershell on the warmer one of my Rab Bags for increased damp protection.The Rab Top bag being for summer use!