I'm thinking the Black Diamond Oneshot, too. It's small and light, freestanding (so you don't have to stake it out, and therefore acts similar to a bivy so you can dig a trench for it easily), has a low wind profile, is tight so there is no flapping in strong winds, and probably strong enough for snow loads. Thing is, it's made of Epic, which many have said is not waterproof enough in sustained rains. For winter use though it may be ideal.
Another light tent you might consider (besides the TarpTent Scarp 1, is the Terra Nova Laser Competition, which Steve Perry used in his 2005 winter traverse of the Munroes in the Great Britain. You can even leave the inner behind and use a bivy inside for extra warmth. That way you'll have a full-coverage, single-skin floorless shelter that is strong and very lightweight.
The Wedge sounds good, too, with John' suggestion of cutting out the floor (you can leave in enough of the floor fabric around the perimeter for snow flaps)
I'm curious, though, why, if you feel you can't stake out a shelter (can you can use the Arctic Pack's aluminum rods for snow anchors?) because the snow might be "rock hard", how you are going to be able to dig a trench with a Snow Claw? I'd think getting a long stake in would be easier and then the shelter itself would provide better protection. I've not heard of any arctic explorers using just a bivy on the tundra, and there the wind must be exceptionally strong.