Basically the idea is a race in which the runners need to run as fast as they can but cannot step out of an extremely narrow lane, e.g. 5 inches or so (hence the name - this actually occurred to me as I was walking to work the other day and out of boredom decided to walk on the curb strip only).
This would essentially involve a trade-off between speed versus coordination and balance. (Sort of obscure, but then so is triple-jumping, at least in my opinion, and that’s an Olympic sport.)
So my question is: are there currently any sports which involve that same dynamic and type of skillset?
As a total aside, your post made me think of transforming the balance beam to a medium-distance running event on a really long beam but that would be too dangerous. Instead it made me think of boffo-weapon jousting on a balance beam, which I think would also make a decent Olympic sport. (1 point for remaining standing, 1/2 point if you are the last to hit the ground.)
I actually once saw an episode of Jackass which involved two guys boxing while standing on stilts. Pretty cool, but hard to see it becoming widespread. Not enough potential amateur participation.
I assume the closest event to what you describe is the women’s gymnastics balance beam event.
The problem with the event you describe is, what happens if you step out of the lane/off the curb? Are you disqualified? Can you get back on, as long as it’s behind the point where you got off? (This would not be easy to enforce.) Do you have to go back to the start? If everybody falls off, is it based on how far you went?