Hammock ULers have flirted with 1/2-3/4 length under quilts and used sit pads or packs under the legs and feet. Certainly a viable concept.
JRB has just posted a limited time offer on a unique Torso Length Wearable UQ... A 2/3 length compared to standard JRB quilts, At 12.8 oz it gets the job done at about 25 % less weight. packs to 10 inch long roll of 4 inches in diameter... 3/4 inch baffle height and average loft of 1.5 inches.... all black color.
Perhaps the real beauty is that it converts to a full parka length vest with two way separating front zip...Add the JRB Hood, 2 oz, and JRB Sleeves, 5 oz, and you have a full down parka for under 20 oz.
This is a limited availability item. At this time it is not planned for JRB 2009 line.... Details are available here...http://www.jacksrbetter.com/Torso%20Length%20Wearable%20Under%20Quilt.htm