Mike
Take a look at the Tarptent Scarp 2. 54 oz in three season mode , add another 17 oz for the extra poles for 4 season mode.
Hit the Tarptent link at the top left of this page for details.
There is a nice little video clip of the Scarp 1 here :
http://hikinginfinland.blogspot.com/2009/12/video-tarptent-scarp-1-in-snow.html
9note the pics of the Scarp under the snow)
The 2 is exactly the same but wider...(32" wide for the 1, 52" for the 2)
Install the 2 main pole guylines, and you are ready to go.
Franco

Tango posted his comment as I was typing mine...
I have the Scarp 1 , have not used it in the snow as yet but all reports on that are pretty good.