Hello!
Time to post here once again, as I skimmed over that discussion on assassination and unit bribing missions.
I used Trojan Sheep's Super Spies mod as foundation for my own modding endeavours, which meanwhile have extended the espionage options available in combination with the World of Civilization (WoC) core mod quite a bit.
Unit bribery and assassination (though I call it "sabotage") are among the available options, though not working quite along the same lines as described here (these missions actually were contained in the C++ source code of default BtS, though not activated).
Sabotaging a unit doesn't kill it with my mission, but does a random amount of damage, and sets it immobile for 1 to a few turns; I'll also try to integrate the "sabotage" feature from CivRev, which "un-fortifies" a unit.
Oh, regarding great persons; you can abduct them (either a unit or a settlet Great Person specialist) with my added espionage missions (though this is only available for the Great Spy).
Regarding unit sabotage, there's still another alternative: Inciting a worker revolt, which (will) set a worker unit immobile for a certain number of turns, and (will) lower its work speed rate.
Regarding assassination: I added/plan on two assassination missions: Assassinate an enemy city leader (I added new city leader specialists for that
), which will send a city into revolt for a few turns (and will have additional side effects like spawning immigrant units), and Assassinate an enemy leader (only for the Great Spy); for the effects of the last one, I haven't decided what to do yet (apart from replacing the target leader with a new one if the targeted civ has more than 1 leader in the game).
If you're interested in seeing/using what I turned the original Super Spies into, just drop me a line, OK?
And once again, thanks for your excellent work with Super Spies, Trojan Sheep!