Nathan, I was just kidding. You've always been quite meticulous, and I actually would be very surprised to hear that you had as much as an extra washer left over after a complete overhaul.
To help you with your possibilities, let me tell you why I think what I do;
The TFI does go bad, and is effected by heat, but it is very unusual for it to cause the vehicle to sputter for a while. When they start to head south, they act just like a circuit breaker; when they get hot enough, the open the circuit like a switch. When they cool sufficiently, the circuit closes again. I think replacing it is a good idea, but if you had done that 2 days ago, you would now be thinking you fixed the problem, because it hasn't happened again, and you'd stand a good chance of getting stuck somewhere, wishing you were armed.
The coil is another possibility, but I doubt it. When the ignition coil starts to go bad, it usually acts like a rev limiter. Rather than kill the engine, it limits your rpms. It may run great up till 3k rpms, and then falls flat.
The fuel pump relay is a good possibility, but they aren't effected as much by heat as they are by amps. Over time, metal transfers to the contacts inside, and they get "sticky". Eventually, the relay either get's stuck open, or stuck closed. Still, like anything electrical, there is increased resistance when it gets hot, so if it's thinking about failing, it will be most likely to when hot.
The EGR valve is supposed to be closed at idle, but is open when you are cruising on the highway, or at a steady speed. Since the EGR valve allows exhaust to pass through it, soot and other exhaust crap settles on the valve, making it more likely to stick open, even if it's just a little bit. If your stalling problem happens most often after driving on the highway, or at sustained speeds, and then exiting, what may be happening is that the EGR is open for quite a while, and when you exit, and it should be closed, it sticks open slightly, allowing exhaust to lean out your mixture to the point of stalling. After it cools, and the metal contracts slightly, it overcomes it's "stickyness", and closes.
This is really just an educated guess, since I can't check it out in person, but from what you've told me so far, it sounds more and more like the EGR. See, this also explains why just getting it hot won't make it act up. It needs to get hot, and spend some time at highway speeds.
Did that help any?