I think the influence of the snowbikes is really going to affect what our backcountry sleds of the future will be. The days of building the biggest, highest hp, best hillclimbing sled seem to be dwindling. Not that they won't always have their place in big country such as Canada, but the deep powder floatation and manueverability of the pro chassis has gotten more riders in trees and off some of the big hills.
I love the idea of losing weight, narrowing the plastics and track as long as it still floats. It won't be for everyone, but it will be for a lot of us. MH your wish list is right on.