I'd have to do some searching but a couple of years ago there was a thread about this. There was a link to a pedal/motorized snow bike very similiar to Pappy's illustrations.
If anyone finds it before I do, please repost.
If I recall correctly it also used a tread, snowmobile style, out back and a single steerable ski on the front.
Cool idea, but I'm not into winter sports. I'd rather stay inside and read a good book when that white stuff starts falling.