You may have to stalk and kill your own unicorn to obtain the raw materials for that one Billy. The first two are a pretty hard combo. Have you thought of having one built for you? Even then, I still think you are going to have to be pretty flexible in your definition of "comfortably" at 32 oz.
I have a Kalais, and it is my favorite pack right now, and no way would it carry 40 lbs in any stretch of my own definition for comfort. It is strictly an up to about 30 lbs in a pinch pack, IMO, as well as the makers and Will Rietveld's:
http://southwestultralight.blogspot.com/2012/03/first-impressions-elemental-horizons.html
The above said, and provided your gear is compact enough, it is perfect with a weekender vertical as mentioned. It absolutely does not do one horizontally. The pack is designed as if around a bear can from the beginning. The first pack I have ever had that felt that way to me. It always seem like you have to fit one in awkwardly somehow with just about every other pack of smallish volume. Since a very large fraction of my trip require a bear can, this is pretty major for me, especially when the can is such a huge portion of the total volume.
I think if you changed the carry line above to something like "carries 20 lbs comfortably and 30 lbs in a pinch" you might have a few existing options there.