Historic Enterprises sells all sorts of medieval clothing, camping accessories, and gewgaws. They also are now selling medieval paternosters and chaplets, styled after medieval examples and (in one case) Bl. Alanus de Rupe’s description of a fitting rosary for a penitent.
This is good stuff! And there’s tons of educational info!
The only disadvantage is that, back in the Middle Ages, they didn’t usually include a crucifix attached to the rosary. (Although painted or carved beads often, often included a crucifix depiction.) But there’s nothing stopping you from adding a crucifix should you want one, or painting one on.
Also, some of the reproductions are closer to the originals than others, in appearance and materials. So look very closely at the pictures of the ones actually on sale to avoid disappointment. These aren’t exact replicas but re-creations of the style.
The Chaplets of the Five Wounds or Passion Rosaries are really very nice, I have to say. I bet they’d also be excellent for the Divine Mercy devotion.