...you guys are great. Nate, you are right--hope to put in the windows in a few weeks (where M!ke was a big help last time I was near the car...). Steve, you are right---its not like I ever expect to lock the door (!)...geez, just the thought of somebody breaking the glass if I left it somewhere would convince me to always keep the windows rolled down (!) And Larry, thanks--I saw the other picture you posted of the Pantera cylinder, and read the PanteraPlace article on drilling a hole to remove from the steering column. The stainless trim on mine (around the key opening) has a small dent, and neither am I sure the original key is somewhere to be found. Just curious (before I probably end up mailing to you 
) How are tumblers sized to a key? (are the flat plates each sized?) At least, it was easy enough to find original keys already cut to code. But time to look and see if the original door keys are somewhere around the house...
V8jet, the correct ignition switch is a Magneti Marelli Q148, with off/run/start only. Good news, there have been a couple NOS with keys on Ebay lately, the bad news is that not just Fiat 850 bus also Ferrari/Maserati used them....I thought $250 was expensive 2 years ago (and the ones there are even higher). The knurled bezel is correct. Nate noticed that Moto Guzzi switches of the time share the bezel (but only have off/run).
The heating thing due to the headlamps can be solved by a relay at the fuse box; the wiring now runs from the battery to the ignition switch, then thru the toggle on the dash to the indicator stalk, then back to the fuse box behind the cab, before finally back towards the headlamps...If you want a bit brighter headlamps and also remove the load from the switch(es), you could use the headlight wires now as control to a relay (direct the feeds into the fuse box as the control for the relay, then switch power there at the fuse box). You could do all this without cutting old wires...Or be like me, and just promise not to drive the car at night