Axle mounted alternator?

Unfortunately no. I used to get Racecar Engineering, and that's where I saw an article about it when NASCAR went EFI. And having moved recently(albeit only 1/2 mile) to a newhouse, I recycled a lot of the less interesting magazines... and havebeen searching for things ever since!

And it just occurred to me, Chevy mechanical FI 57-65 used a cable driven pump, driven off of the distributor. I don't know how much stress that could take, and how it affects cam twist, but it could be a potential candidate to drive an alternator. Of course there would need to be a step up gear box or drive arrangement to get the correct speed, but it certainly is doable.

 

I don't think an alternator mounted under the car would do well in wet weather.