Remember, the standard bistable will work with _any_
type of switching
component (relays, bipolar transistors, jfets, mosfets, valves, etc).
Similarly, you can make multi-input gates, which, while not original,
perform the same functions.
Yes, relay based bistable circuits have been around since, well, the
beginning, and tube based flip-flops could be found in early radar sets.
William Donzelli
william(a)ans.net