So I've been seeing a lot of other cheats and hints saying that you can only get the Tundra Beads in the ark of Yamato.

This is a big fat lie.

If you want the Tundra Beads in an area that you can actually enjoy them in, you need to have beat Lechku and Nechku in the wawku Shrine. After you do this, go to Sei-an City, in the Commoner's Quarter. Look around for the Weapons Dealer (close to the entrance by Ryoshim Coast) and select "buy". If I'm not mistaken, the Tundra Beads should be there.

This is the most powerful rosary in the game, so knock yourself out.