Actually, in some ways you folks are behind the times and are re-inventing the wheel.
Back in the late 70s or early 80s, Lincoln came out with a town car that had two alternators.
One 14.5 volt one for the car's electrical system, and a 3 phase AC one that put out either 120 or 240 volts.
Its been so long, I don't remember which.
The car also had a very special windshield. In the safety goo between the two panes of glass, they put a quantity of very fine gold dust.
I was never able to see it, but some folks said that if you got the light just right, you could see a gold tint.
Anyway, there was enough to be weakly conductive. When you hit the defrost button, it put the high voltage output from the second alt across the windshield, and caused it to warm up.
Of course, being in Fl., I only got to see it work a couple of times. But with the engine running at fast idle, it only took a few seconds for you to see results. And, unlike the defrost grid on rear windows, it was a surprisingly even effect.
Gold was fairly cheap back then compared to now, but even so, I would hate to think what a replacement would cause if a rock hit it.
On a related note, I saw an article about some folks that are developing a wiperless windshield.
Details are being guarded right now until all the patents are in place, but it seems to involve an ultrasonic transducer that vibrates the glass at about 30KHZ, and the rain, snow, and bird crap just bounces off.
