KBK update for Monday, 15th June
UncleFan found a store in Lebanon—Incotel Electronics—selling a couple of Cherry types: M73-0800 and M91A-11NN. On further inspection I also turned up M76-0899 and some RAFI and Siemens models. The nature of M76-0899 can’t be confirmed until it arrives, but based on the data for M76-0890 (a catalogue part in 1982), it should be a 1A+1B alternate action switch.
M91 however was an interesting find, because until now I believed that M91 did not exist. In fact, the part number chart for Cherry M9 has a gap where M91 could be listed. The way that the lines are drawn suggests that the M91 entry was not removed, and some of the boxes of M91 switches at Incotel were made in 1986, after the chart was last revised. This would suggest that M91 was considered, and nobody ever filled that box in after it was made available.
Incotel seem to have a good supply of M91A-11NN (with clear stems) in 800-piece boxes dating to 1985 and 1986, as well as an unspecified black stem version that may be M91A-41NN (as per the switches in the Ultratech Miniprint).