The issue is that even with the top up (and with the degree of cold we get up here), I don't always get sufficient heat into the cabin, when the heat volume is engine speed based. Driving the car, I don't always get the chance to stay at high revs for long, if I want to have some regard for speed limits.
Jim: I do have seat heaters (three settings, no less) and there are two outlets that I asked Henry to install, so an electric blanket for the wife was always in the plan. That was an idea I got from you when the car was being built- thanks. But I can't see me using one - how manly would that be? 
Ray: The Davis system of fresh/heated air needs to be done during construction, as it's not a very easy retrofit, as I understand.
Gordon: Your idea might work, as that set up is small enough. I've already mentioned it to my shop, and I might pursue it more.
The weirdest thing about my car, is that during a cold rain, the engine for some reason cools right down, even to below its normal operating temp (180), so I get even less hot air. Rain water does not get into it from the top, so it must get sprayed from below or something.
Oh, well, it's a great car to drive regardless.