I haven't really found anythig I'm totally comfortable with yet. For some time I've been carrying it on a Protech strap with a silnylon drybag as a case. Invert the bag and cut a few holes for the strap and it keeps most of the weather off. It will depend on the camera of course.
Its going to be heavy, but as a few people noted last year much to their amusement I was carrying 20kg of Ultra Lightweight gear - so whats another Kilo or two?
Perhaps I'll start the Heavy and Happy(ish) brigade?