I have a possible experiment that could serve as a solution to this problem.
Simply designate a place as the "noble zone." A place where every useless, lazy, horny noble lives that contains everything they need.
Put them in, lock a door, VOILA! Isolated nobles.
It's like a noble zoo. Occasionally dump supplies down there, or alternatively, sacrifice a few dwarves so that they have their own personal farmer, weaver, etc., all in one isolated area of the fort where the kids can't interact with the rest of the population.
I'm doing this for my current fortress. My nobles are locked away in a vault underground, isolated from the rest of the fortress. They have a well, a farm, and their own tiny but lavish bedroom and dining rooms. I've used dwarf manager so that they will farm their own crops. As punishment for being nobles they don't get booze, only water from the well. They also are only allowed to ever eat the same food. I hope they like strawberries!
Within this vault are all of the levers to the various parts of my fortress, including my traps. There is absolutely no way to access this vault from anywhere else on the map.
All the nobles do is chat with each other and furiously pull at levers whenever I tell them to pull a lever.
Why use a repeater? My death traps are powered by immured nobles.
The stone walls are thick enough that you cannot hear their screams for booze.