I wonder if it would be possible to implement flexbody telephone poles that would react in a similar way to the video below. I'm not sure if it would cause a large FPS drop if added multiple times in a map, but it would be cool either way.
Im not sure how well correctly sized telegraph poles would work as they may be too thin for the simulation. But if you make them a bit wider it could be interesting. I guess Nadeox1's barrel kind of shows vehicles crashing into objects.
They are definitely possible, I'm not sure how you would make the wire though. Unless you make a custom pole layout for each map that has interconnected poles. I wouldn't see much of an FPS drop come from this either, as the pole would have a low amount of nodes, and the "vehicle" would only be active when you're relatively close to it.
I would have to disagree about using jbeam structures for cables. They would add little to the game and take a disproportionate amount of cpu power to produce. You could just stretch one 3d model between the top nodes of each pole with nothing connecting each n/b structure using flexibodies to save a little fps. I think lampposts would be a much better idea because modern lamp posts are designed to crumple (at least in the UK) meaning they would have a more noticeable effect, they would also not require connecting together meaning you could have lots of "vehicles" that only simulate when you are close to them. This wouldn't work for power lines since they would have to be connected to figure out the physics for the line itself.