Randall Monroe in one of the footnotes of What If? 2 mentioned that one light-nanosecond is very close to one foot (11.8 in vs. 12 in), and "propose" that we should just redefine foot as the same as light-nanosecond.

I wonder if one can get ahold of a Hopper Nanosecond today or if they all got identified as junk wire and thrown away.

Luckily, creating additional nanoseconds is cheap. The value was always in their symbolism, not in them being given out by admiral Hopper herself.

Says you!

I do! If you're interested, I'll send you brand new nanoseconds including an Official Certificate stating that they are Officially Certified to be equally long as Hopper nanoseconds (within reasonable manufacturing standards tm of course).