Thought I'd share, as I feel like this project turned out nice and was super-easy. I wanted something to match my collar, which would be cheap and not require mods of any sort to my box. I used a pine 1x6, pine quarter-round, and a pine 1x2 from the Depot. Additionally I used a couple of cheap rubber bar liners, glue, stain and poly I had left over from my keezer collar. Only tools I used were a chop saw, sandpaper and a scraper. I mounted it with angle brackets and a few strong disk magnets I had around the house, and it's holding tight even with a few drinks sitting on it!