I've done a bunch of these ghost switch systems. They're fun to sketch up and then work the sketch for bugs and unintended operation, correcting errors as you go. I began with the "horn activated starter interrupt" in the Relay Section of this site about 8 years ago. I've expanded and improved my systems continuously, with about 15 installations in my or friends cars. No two systems have been exactly alike. It's fun, but a strong understanding of relay-relay logic and automotive electrical systems is very helpful.
Geepherder's diagram is simple and workable, but there are some drawbacks:
A: The high beams and wipers will operate when you use them to actuate the ghost switch thus giving away the "what needs to be done" to start it.
B: I like to use latches to keep the system active until a door is opened. I can stop the engine to order my burger and restart without doing all the "stuff" again. Also helps with service work. Leave the window open and reach in to start/stop the engine during service.
C: If you have a Remote Starter, you have to incorporate a bypass to activate the ghost switch with the Status from the R/S.
D: You should have a hidden bypass switch in case of malfunction. Or use N/C relay contacts, and a switch (or a fuse in the stock panel, my favorite) that removes power to the array which defeats it as a bypass.
It can get complicated in a hurry. The system in my Super Duty has 12 relays. It interrupts both Starter and ECM power. (I know, we're not supposed to interrupt ECM. But the ford starter solenoid is right on the fender. Too easy to jump). It requires two actions to defeat. It has bypasses for the R/Starter. It remains powered up for the 10 minute duration of the DAB. And the last line of defense is an interface with the GWA on the Viper so that if they DO figure out the required action, it STILL won't start if they don't have a fob to disarm the Viper, or can't find the button for the disarm.
Sorry for the TLDR. My point is that there's quite a bit to a well thought out system. Geepherder's deal will accomplish what you've asked for, and I commend him for taking the time to create and post the diagram, but it's almost too elementary.