I love it! Very ingenious. IMO the variables are almost endless. Different woods, different leathers or materials, and different rods could be available so there's something for everyone. My mind sees a high-end version with alligator leather, burl wood ends, and polished brass tubes, or even glass rods! It seems also that thinner, softer leathers might "cradle" the pipes and conform to shape easier... and easier to work with ... maybe. There is a plethora of types of woods you could use. Gromets are also available in different materials. The metal rods can also be tubes, and probably cheaper. There is brass, stainless steel, carbon fiber, and glass rods (and they come in different colors) to mention a few. Gosh I'd be up for days with all kinds of variations dancing in my head.
Wonderful, just wonderful! I wished I had thought of it! I'm so happy for you. Please show us all your variations as they are made.
One more thing. There is a leather tool you can buy that rounds over the sharp edges of thick cut leather, you might look into that.