It seems like the most difficult part of making the strop was using the cloth to make the buckles for attaching the D-rings. If you make additional strops, you might consider making the buckles out of leather. It might increase your cost slightly, but it would decrease your workload. A 3 1/2" x 9" piece of trim leather sould be sufficient to make two buckles and should cost less than $10 Canadian.

I have a Tony Milller linen strop that has flax linen fabric, but leather buckles. It is quite nice. That one is fabric only, no leather component.