Last month, I had to build a programmer for a microcontroller. It required only three components other than the MCU. There was an oscillator, a MAX232A, and a 74HCT125. I had no trouble getting a suitable oscillator, and I generally have a few MAX232's around. It took weeks to find the HCT125, though, given that I didn't want to pay $10 for shipping of a $.25 part. In the meantime, I'd built the thing with a GAL16V8. Overkill, well, true, but I didn't have to deal with the widespread search.