[ctdonath2]

they're nano-tubes. Just a bit short for the job.

They're also getting longer. Was just a few years ago that "buckyballs" were first created/discovered, and didn't take very long before they were extended into "nanotubes" a few millimeters long. Just a matter of time before they're cranked out by the mile.

[Gorjus]

Just a matter of time before they're [nano-tubes] cranked out by the mile.

I guess so, since it's 'just a matter of time' until the heat death of the universe so that's not much of a limitation, and I also expect it will eventually happen.

However: 1) Carbon nano-tubes are still not strong enough, and nothing in known science is strong enough. 2) The biggest problem is still maintaining angular momentum. 3) I already said I think the technical problems will be solved. Though it is indeed, 'a matter of time.'