… what was the latest terminal produced which rang a physical bell rather than beeping through a speaker?
To my memory real bells were only a thing with TTYs. After all, ringing a bell is just another lever to be moved when a character comes along - the very same way as any other printable character.
I would not know of any Glass TTY that had a mechanical bell - after all, as soon as there's a TTL circuit to do the job, adding a flip flop and a resonator is already way less expensive than adding any bell mechanic.
That black bulky unit right in the middle produced what DEC calls a 'audible tone':
1.2.2 Bell Operation
Receipt of the Bell character causes an audible tone to be produced. A separate tone burst is produced from each of up to eight bell codes received in succession.
(From the LA36 Manual)
Each 'audible tone' is 106 ms of 2400 Hz. This is true for all DECwriters (LA30, LA36 and LA120).
But there is a nice 'intermediate' step: Some early (high end) CRT terminals of the 1960s had circuitry that synthesized not just a beep but a more sophisticated bell like sound. For example die Siemens 8150 mainframe terminals and follow up series (8160 and early 9750).
I think the Teletype Model 43, ~ 1980, included a mechanical bell. It has been a while - I got rid of mine around 1986. The service manual references a "bell coil" and "bell plunger" in trouble-shooting for "Does bell ring under any conditions (CTRL G RH margin, etc)?", which implies that it is a mechanical bell of some sort rather than a purely electronic beep.