The big problems I had with down stuff I tried is that it didn't take much dampness for it to all but stop working, and on my last outing we had another torrential rain that penetrated even the most waterproof materials we had. I wouldn't want to get caught in a storm like that with down.
At the moment, I'm thinking a Ultralamina 15f bag with a set of fleece base layers and a good quality pad. But with that in mind, if anyone knows how I could fix the moisture problems or seriously sees that set up as pootentially dangerous, I'm all ears.
I'd rather be wrong than cold.