Well, the first design of the bag is finished, sans hood. Because I don't have pictures to show, here's a rough estimate of what it looks like.
The top and bottom are 6-sided shapes and look like someone put the long ends of two trapezoids together. The lower (and larger piece) is 60" high, 24" wide at the top and 12" wide at the bottom. The top trapezoid has a width of 24" at the bottom, 12" at the top and a height of 5".
The bag is about 18" at my hips and is about 5" taller than my height (at my shoulders). The design is styled to wrap around my shoulders. I will be making an insulated jacket-hood for the bag. The sides ares 10" high and ~75" long. They go from the bottom of the long side of the shell around to the top of the smaller trapezoid, leaving a 12" space open for the hood. The footbox piece is a rectangle 10"x 12".
Without the hood, the bag will require ~6600 in^3 of down @ 2.5 inches of insulation. That's approximately 9 oz of 800 fp down. It is also a rating of at least 20 degrees, my goal. According to jardine measurements, it is an effective temp rating of o degrees, which I skeptically view as generous. Anywho, I need the bag to be able to handle sub-freezing temps but I don't expect to take it on a winter expeditions. It is going to be a tough, workhorse 3-season+ bag.