I went with the NAPA NP KS6180 keyed ignition switch that devilman96 suggested, cost me $18.80 at the local NAPA store. The NAPA switch takes a 3/4" double "D" mounting hole (like a round hole with a flat on each side to keep the switch from rotating, the top and bottom of the hole are round and 3/4" apart, the sides are straight and a little over 1/2" apart). I used my Dremel tool to enlarge the original accessory switch hole just enough to fit the NAPA switch. I didn't take much metal out, I could reinstall the original switch and switch plate and you wouldn't be able to tell it had been modified. As you can see in the photo, the hole for the pin on the original accessory switch that locates the switch plate is visible, so there was not much metal taken out of the dash.
I connected both #11 circuits (+24V) to the "Bat" terminal of the new switch, circuit #1 (feed to alternator & manifold heater, actually marked 55 on my Deuce) to the "Accy" terminal, circuit #27 (starter, fuel pump, low air pressure, front wheel drive and gauges) to the "on" terminal, and ran a jumper from the "start" terminal to the starter relay circuit #74A. That way I can start the truck with either the ignition switch or the original push button switch.
The connectors to the original switch are military rubber female connectors. I didn't have any military style connectors at the time, so I used .157" dia. male "bullet" connectors (NAPA/Baldwin #784341). They snap in nice and tight just like the military connectors, but only cost $1.83 for 20 connectors versus the $1.00 each Saturn charges for military connectors. The NAPA/Baldwin #784353 .157 dia. female connectors are also a perfect fit to the military male connectors.
After I installed the NAPA switch, I painted it OD to match the dash panel, it almost looks like it belongs there.