Check out ElectricGT.com
They have a conversion kit already for an electric motor. Looks kinda like a V8 engine with everything included. very cool set-up, very pricey too.
That looks like an awesome kit. Gonna show that to a buddy for his incoming bronco project. We finished installing the bumper and winch from 4Wheelonline onto his Wrangler and sold it so he got some budget for the Bronco.