..or the plug-in 12v heated snowmobile suits, i've always pined for one, but it might not fly with the fashion conscious or the business commuter crowd
..defrosting windows with the built in elements in the glass is a good start, but i think you'd still need to be running fans anyway to clear the condensation and fog from the glass
it's also disappointing to get home from the grocery store with the fuit and veggies frosted and and wilting, so there might still be a need for some minimal base level of cab heating...
Around here most people start their trucks with remote control starters and then idle them for a good half an hour or more so they are like sauna's when they scurry across to them. I think it's a pretty big thing psychologically that helps people deal with winter. I don't know what you would do to temper that expectation. Maybe a mains electricty plug in pre-heater to get it warmed up a bit for the commute.
Some of the old volkswagon vehicles had a seperate
gasoline heater rather than using engine heat. They were scary. But maybe a compromise cold-climate add-on would be a small propane or natural gas tank for the heater.
The heat bubble in vehicle is sort of an old idea made new. In the horse and wagon days people had metal boxes with upholstery on the outside. They would fill them with coals from the
wood or coal stove, then set them down on the sleigh floorboards to rest their feet on. Big heavy blanket or calfskin draped over top of that that people could tuck over the seat and up to their chins and you had a nice heat bubble for cutter ride in to town. Come to think of it that would work for the home office too, if you had a fire for a bit in the morning.