Same as Moke here. For years I used a pair of 2' long steel threaded rod extensions I'd made up, with a jam-nut-locked female connection nut on one end and a short section of male thread extending past a lock nut at the other, covered in heat shrink (thick on the nut ends, thin along the length of the all-thread center portion). These were useful as short stands mounted in a tripod foot and as stand extensions, but rather heavy. The outside of the thick heatshrink covered connection nut would fit nicely into the female socket of a superclamp or the folding foot, secured with a thumbscrew. I now mostly use a lighter and more adjustable single telescopic extension, which works better for clamping to railings and atop a stand when required.
The nylon threaded rod is not likely to be stiff enough for that kind of extension application under load, but shorter sections of it should be fine for mic-holder/mic-bar/shock-mount applications, and the lighter weight is a bonus. Take a bit more care threading nuts onto it so you don't cross-tread it.