Gawdz! I never thought about that very logical method of transporting large stones overland... wait 'till winter, and sled them! Brilliant!

In terms of using the snow and ice as the building material itself, obviously it's a very ephemeral structure, unless you are up above the arctic circle, and even then you would see your efforts melt during the brief summer. But somehow there's a kind of zen quality to allowing your efforts to be destroyed by the elements.. like the mandalas the Tibetan monks create grain-by-grain, meticulously, only to intentionally destroy at the end.

My Quinzees (snow caves) sometimes will last most of the winter, sometimes they'll cave in after a week or less, depending on conditions... here in New England you can never know what that will be exactly- and it also hinges on the kind of snow that falls, wet or granular, etc. Sometimes I'll build a big one and then it'll fall and I'll build on that ruin when the next snow falls.

Alone with a shovel, and a sufficient amount of snow, I can put one up in about six hours, big enough to seat six adults inside. I have pictures on my site at http://www.handofdave.com