Hrm... On the ignition switch plug, there is a main supply wire. There should also be outgoing wires for the ignition power, acc power, etc. The blue outgoing wire should run to the starter solenoid. If I were you and I just flat out didn't worry about the Jeep being keyless (which is a long shot- what if a kid climbs in and flips the switch?), I would wire the ignition/acc/etc circuits to a switch fed by the main power supply. Switch on, ignition/truck live. Would have to be a HEAVY switch, be sure and check amp ratings and use proper connections. Then, I would mount a horn button on the dash with a supply wire from the acc circuit (hooked to main switch so that starter won't turn without ignition on) and the outgoing wire as the blue starter solenoid wire. That way, to start it up you just flip your toggle switch then press your button.
Does that make any sense? Feel free to try it, but again, fixing the factory lock cyl would be a safer option for anything but a dedicated farm truck.