Mine are in store at the moment, so I can't check the ending dates, but I do know that all of my Nikon backs work. They are still very much in use; I like to put a date stamp on the first frame of a roll, and on the first frame of each session if I use a roll over several days. The backs I have are:
MF-12 (All models of the FM/FE/FA family except the FM-10 and FE-10)
MF-16 (All models of the FM/FE/FA family except the original FM and FE, FM-10 and FE-10)
MF-15 (FG)
MF-19 (F-301 and F501)
MF 26 (F90 and F90x)
As of yesterday I also have the mF-29 for the F100, which I believe works, but I haven't managed to get the battery into it yet.
The only Nikon camera I have with a built-in non removable back, the F50D, doesn't work.
The Canon Data Back A is weird, in contains no clock, you set the date manually with three dials on the back. It only has two dogits for the date and is limited to certain ranges which seem to be :79-90, 0-9, roman from i-x, a-g and what looks like a square.this fits the ae-1, ae-1 program, at-1 and a1, but not the av-1 or al-1. it has no built in contacts to connect to the camera, but is triggered by a short jumper cable to the camera's pc flash connector, like the Nikon MF-12. This is one area where Nikon did a better job than Canon!