Thanks to all of you, I got some good leads from this discussion. The alternatives to lead batteries that I didn't already know about when I started are...
1) NiFe (Edison cells)
Advantages: non-toxic, durable
Disadvantages: not as efficient as lead-acid
To research further: where to get nickel-oxide or how to make it out of nickel (and then, in turn, where to get nickel).
2) Air pressure
Advantages: non-toxic, mechanical
Disadvantages: high pressure gas, increasing resistance as tank fills, uncertain efficiency
To research further: how much volume and at what pressure (25* C) you need need to have in order to retrievably store 1 kWh.
3) Flywheel
Advantages: non-toxic, mechanical
Disadvantages: high-speed moving parts
To research further: how many kWh a flywheel the size and mass of a truck tire in a low-pressure compartment can retrievably store spinning at the highest speed permitted by its design; what this speed actually is; how to transmit the relatively constant rotation of a windmill to the constantly accelerating rotation of the flywheel during its charging phase.
(I knew about elevated water and suspended mass approaches, and unless my calculations were wrong, the sheer size of the system needed to power a residence would be prohibitive unless you happen to already be near a hill or cliff)