WinterWren FF bag as a pullup bag?

Has anyone used a Feathered Friends RockWren or WinterWren as a pullup bag for hammock camping? Opinions?

http://www.featheredfriends.com/Prod...winterwren.jpg

With the drawstring foot box and half zipper I would think that this bag would be the ticket for a complete overbag. You can even get it made with Event fabric! Just don't look at the price!

I found this one and have been considering it for an under quilt for my hammock. It too has a drawstring foot box!

http://www.mec.ca/Products/product_i...=1172713618480

Turk has used that bag and even converted it to an underquilt. Search www.hikinghq.net for details.