Motorcycle engine as an ICE range extender?

If you drew up plans for an EV using twelve lead-acid, 12-volt batteries, and then (prior to purchasing batteries) added $3,000 to the energy system budget, what additional battery options are there and what impact would the new options have on range and performance?

Assume a mid-size 4-door sedan that would get about 60 miles range with the initial lead-acid set-up.