Chimpac
Thank you for swallowing your pride and showing yourself wrong.
As your pictures prove, expedition do indeed use "expedition" tents (semi geodesic design exactly the type I recommended...) and as a "mess" tent at altitude can use a pyramid tent ( just for the record, the Black Diamond Megalite is a pyramid tent, not a tarp and not a shaped tarp either... ), however there is no chimney to be seen and are not considered safe enough to be used to sleep under by organised expeditions in those areas (individuals may choose to use one).
A third point shows that you greatly lack comprehension skills.
If you actually read what I wrote when I showed those "kite" pics, I explained that they had nothing to do with this thread (just like your input...) but it was just something I was doing in between posting,
The type of tent that the OP was after had already been spelled out many answers before and as you just confirmed it is indeed a semi geodesic/multi pole design.
Rick D ,
caving in/snow compressing against the fabric is the reason why neither pyramids nor tunnel tents are used (generally...) when heavy snow is expected (that is both wet or a lot of snow...)
Again some people forget that the often quoted Antarctica is actually the driest continent on earth, that is it does not snow very much at all down there.
If you look at the Mountain Hardware "expedition" tents you will notice the multi pole design in the smaller ones and the full geodesic in the larger ones , all designed to deflect high winds and shed snow.
(just noticed that the inner (tent) of the Satelite is now white with orange stripes...used to be blue and white)

http://www.mountainhardwear.com/expedition-tents/tents-expedition,default,sc.html
Franco