Originally Posted by Seggybop
I'm thinking the Sturmey Archer AW is probably it, but that's only a guess. Any ideas?
The AW is on target for a fine, bulletproof hub.
It does have one fault however, and that is it's tendency to slip if the gear cable is even slightly misadjusted - which, as you mention you'll be putting considerable stress on it, will be a dangerous combination.
However, in the mid '80s (forgot exactly the year), the driver and clutch of the AW were revised, eliminating any possible slip between gears. This variant is as perfect as the AW hub gets, and is what I would suggest you use.
Take care,
-Kurt