Polar fleece wont compress much , down compresses a lot, Synthetic Fiberfill is in between.

this a tapered foot quilt. and the insulated sleeping pad you will have are reasonable
http://www.nunatakusa.com/index.html they have kits where you would wear your Down Coat
and just bring the bag for the waist down.

or the pad sleeve and bag/quilt combo :http://www.campsaver.com/itemmatrix....8&MatrixType=1