Look at Ray's stuff. He's a strange guy, but he's got the experience to back up what he says. His quilts don't have a hood built into them, but he sells a kit to make an insulated bomber hat that would act like a hood.

I know what you mean about your arm. I dislocated my shoulder years ago and it still bothers me once in a while. I like Pika's take on bags-a full zip turns one into a quilt with a hood and foot pocket, never thought of it that way.

I like a mummy bag, but probably would sleep better under a quilt because of the way I sleep.

A good balaclava or fleece hat can substitute for a hood. I'd choose a quilt over a rectangular bag.