Lots of good idears here. And some sketchy ones. But I guess we need to explore the sketchy ones, too, just to rule them out. As tempting as a 12-gauge reality check under the seat might be, I have a forgetful wife and a curious child to consider.
In terms of preventing theft, anything is probably better than nothing, especially if the goal is to discourage the sort of E36 M3head-grade, crime-of-opportunity behavior that seems most common around here.
Interrupting the positive side of the ignition circuit is good. Interrupting the ground side might be better, if possible, considering most people are likely to check for power but assume the ground is good. Or maybe add a switch to short the circuit to ground and pop the fuse if someone attempts to start it.
Older EFI Toyotas had a fuel pump relay that could apparently be interrupted, resulting in enough fuel to start up and then immediately shut down. The theory 20+ years ago was that starting the engine would count to either insurance or law enforcement as attempted theft, whereas breaking in and mauling the lock cylinder might only be considered vandalism. Not sure how universal that is or whether the relay circuit mod is applicable to anything else. As others have mentioned, a carbureted vehicle might start on the fuel in the float bowl even if the feed is interrupted, so the result would be roughly the same.
In the case of the OP's Jeep, we have a distributor to play with. Swapping a few spark plug wires around might be enough to dissuade anyone who doesn't already know where the #1 terminal is on the distributor cap and which way the rotor turns.
Quick-release steering wheels are cool. How about a quick-release shift lever, or maybe brake or clutch pedal?
Preventing theft is one thing. Following up once it's gone is another issue entirely. I know Apple users have the Airtag option. I'm on Android and don't know enough about other options available to us. It would be nice to have something pinging GPS and not just networking via Bluetooth with other Samsung Galaxy or Android devices so you could still find it even if someone left it in a field and walked away. Is a Tracfone or similar burner, coupled with Life360 or some other family tracker app, a realistic option?
I had a dream last week in which I had three vehicles stolen in one night. The fact that they were all stolen from the same parking lot - a Kmart parking lot, no less, in a town I haven't lived in for twenty years - probably says more about my own unresolved issues than anything else.
