I must thank you all for a most interesting thread, I read it in it's entirety waiting for the laser to finish cutting at work today.
I will share a couple I have had to try on my own.
I used to drive a 1988 Mitsubishi Mighty Max. Those who are not familiar with those little trucks, they are more commonly labeled as a Dodge D50. They are not common trucks by a long shot. Mine had a 2.0 liter 8 valve 4G63 engine, which has the infuriating issue of bad fuel pump location. The mechanical fuel pump (Carbureted engine) is bolted to the side of the cylinder head. The intake manifold is also bolted to that cylinder head, same side as the fuel pump, leaving approximately no room to get the damned fuel pump out. Another bigger problem, was the fact that nobody had said fuel pump in stock, at least no auto parts stores had parts in stock - more on that later. One instance when the pump died, my roommate and I were far, far away from anything, having only the toolbox on the back of the truck, and it was either a 50 mile walk to civilization, or get creative and make the truck run. I had several feet of spare fuel line for reasons I cannot recall, and a few bungee cords, and a gallon gas can. I set the roommate to getting gas into the gas can (Older Japanese trucks have a drain plug in the gas tank) while I used the flashlight on my fancy Keyocera Rave cell phone to get the fuel line off the carb, and plug the ones from the fuel tank. (Why most cellphones have cameras, and not flashlights, is baffling to me. A flashlight is much more useful.) We fed a fuel line down into the gas can, attached the other end to the carb, and strapped the gas can to the roof of the truck - bent the back corner of the hood up a bit to get the hose in with the hood closed. We had to stop to fill the gas can a few times. After that, I put an electric fuel pump on the truck, and never had that problem again. I learned a bit later that to get engine parts for the truck, one didn't need to go to an auto parts store - you were better off going to a forklift shop. The Mitsu 4g63 engine is used in a few forklifts, such as the Clark GC25, a few Mitsubishi lifts, and smaller Caterpillar lifts.
With the KLR I had an issue related to the fuel petcock - the vacuum operated one. Local motorcycle shop didn't have one that would fit. Took the factory petcock apart, just to see what was inside to see what I could do with it. Ended up going to the local Industrial Supply Shop and getting some fuel-proof rubber from them. Cut a piece and replaced the vacuum diaphragm with the rubber, and it's not been an issue since.
Another favorite - the ignition coil started to give up the ghost on my Chevy truck. We would go about six miles, and the truck would shut down. 30 minutes later, it would run again like nothing was wrong. For a week I kept the coil in the freezer at home, put it in the truck to drive to work, and put it in the freezer at work.
Reading the stories posted here has made me think - most people cannot do these things. The wherewithal to see a problem, and think of a solution that involves only the things in arm's reach, is not a normal ability. I grew up in a family where if something broke, we would fix it - no matter if it was a toilet, doorknob, car, computer, radio, VCR, etc etc. If it could not be fixed, we tried anyway - what is there to lose?