Fibers are basically just execution stacks like greenlets from python so I would imagine you can clone/copy them.
Nice write up, I think it will help people get more fibre in their D diet. :)
A little write-up I just did on something I thought was pretty cool:
Combine Coroutines and Input Ranges for Dead-Simple D Iteration
https://www.semitwist.com/articles/article/view/combine-coroutines-and-input-ranges-for-dead-simple-d-iteration