I was also requested to make a set of "Pater Noster Beads" by the customer who requested the Decima Rosary Cross. In the following pictures you'll see the results. You'll notice that I made the Cross a "Decima" as well, so that the beads could be used both for the repetition of the "Our Father," as well as to pray a decade of the rosary.
The Pater Noster beads, from what I've been able to gather, originated in Ireland during the Middle Ages. They were a way for laymen to participate in the monastic life. In monasteries the entire Psalter (Book of Psalms) was read daily by the monks - it took some time for the monastics to develop a cycle of readings from the Psalms so that in some places the entire Psalter was recited weekly, whereas in other places it was recited monthly. For laymen the monks recommended that they simply recite the "Our Father" either 50 or 150 times (depending on who you talk to).
The Pater Noster beads were originally knotted cords, but over time the practice of using beads developed. I have read that they had anywhere from 10, to 50, to 150 knots or beads. Originally these knotted ropes contained no divider beads or knots, but over time people started adding dividers and praying the "Hail Mary" or "Glory be" on the dividers. Eventually the (Dominican) rosary developed - perhaps as an offshoot of the Pater Noster beads - and replaced the Pater Noster beads in popular piety. Incidentally the rosary also replaced the Pater Noster beads as a suitable replacement for the recitation of the Psalter or the Liturgy of the Hours.