I followed this thread with interest when it was current.....I knew sooner or later I would need advice about fishing wires through tight spaces.
We ran across this situation today, trying to fish a wire from the basement of an old house all the way up into the attic. We eventually established a straight shot inside an old wall about 20' vertical distance. The wire was to be passed through a hole in the basement, straight up through the inside of the wall, and exiting through a narrow gap (about 1") in the floor of the attic. We knew it was a straight shot because you could see a light shining up through the hole in the basement.
We tried and tried to get a fish tape down the path, but it was impossible to hit the hole at the bottom to make an exit. A fish tape is too flexible and impossible to steer. We thought of dropping a line with a weighted chain on the end, but did not have anything available. Nor did we have an old fishing rod.
What eventually worked was one of those collapsible tent poles...the kind with the bungee cord inside. The advantage was that it could be assembled in a tight space while feeding it up or down the hole. It was thin enough to easily pass through a tight space, and stiff enough to make it steerable. We taped the joints as we fed it in, so that it would not pull apart while being retrieved. It was easily passed all the way up into the attic. We taped a string on the end, and then pulled the fish-line down while retrieving the tent pole and re-collapsing it again in the basement as it came out. Piece of cake!!
I've never seen this described in the electrical world, but I thought I'd post it in case anyone else could use the same idea! Happy fishing!