Not quite at the same level of Serious Bizness and a broken Nomad frame in the outback, but a couple of years ago I bought a city bike from a local social enterprise which tidies up and re-sells donated bike. Mine is a 12-year-old Norco Monterey hybrid. After a day or two I noticed a braking from the stem/head-tube area. Looking at it more closely I saw that there was a 2" crack from the top lip of the head tube at front.
I guess I could have taken it back, and asked for something similar, but at the time, this was the only bike in the shop that suited what I needed. So, I mixed up some JB Weld, pushed it into the crack, clamped the sucker so it oozed a bit, smoothed the lot and let it be. The next day I sanded it down, covered it with a nice bit of silver/grey reflective tape, and since then, no creaks from the head tube.
Not quite I'd recommend Frank add to his spares kit, at least for the type of problem he had, but JB Weld is brilliant stuff.