Still, I did not really like the options I found so I decided to put together two IKEA items and attempt to make my own.
Step 1: What You Need
* An IKEA RIBBA shelf
* An IKEA TJUSIG coat wall hanger
* A saw (handsaw or similar)
* A pencil (or other writing instrument)
* A screwdriver
* A measuring tape
* Some paint and brush (paint colour and type to match shelf colour)
* 2 or 3 wood screws
* Letter or Number stickers (optional)
Step 2: Measure Twice, Cut Once
Cut the marked end(s) with the saw and use the sand paper to smooth the cut edges
Verify the cuts align with your shelf
Apply the paint (in my case, it would be white, glossy paint) and let it dry overnight
Step 3: Join Pieces
Since this was my first attempt, I marked a dot direclty below the pre-made wall-hanging hole and drove a wood screw all the way through the shelf and into the hanger.
For future units, I would likely drill a tiny hole first for a better finish
Step 4: Final Product Mounting and Decorating (optional)
Also, you can add pictures of your races by purchasing the IKEA RIBBA frames (created for the frame holder shelf)
In the final picture, you can see I went and bought a metal ring to hold my race bibs and use one of the hooks to put them all there.
I hope you enjoyed this instructable.