I've been thinking along the same lines, mostly considering what I'd do in a succession game, but my main idea is to make a hallway below a water reservoir. The hallway being one tile wide and alternating pressure plates and flood gates. Attach levers to each floodgate and attach pressure plates to bad things in your fort. Such as flooding areas in water or magma, releasing everything in the zoo, atom smashing the mayor's room, you know, interesting things. I'd probably try my best to surround the hallway and reservoir with large amounts of water from a different source or magma and make it so the only way into the pressure plate hallway is through the filled water reservoir. An alternative is to make the floodgates block short hallways with pressure plates so that the traps don't have to trigger in the same sequence.
I'd then proceed to place as many bridges, floodgates, hatches, doors and other objects attached to levers as possible. I'd link my trap levers to things like the main gate, the danger room or anything else I think someone would be likely to pull. Of course all levers would be completely free of notes. This would make pulling a lever always be a gamble.
The other thing I'm going to do in my next fort is place food and booze stockpiles in my baron/king's quarters. And block his quarters with an indoor moat and bridge. The bridge lever would be outside in the main dining hall, so in case of emergency I can lock up my nobles and wait for migrants to repopulate my fort. Sort of like a panic room only my nobles would be more like prisoners. Well. Exactly like prisoners.