Hi Jeff
Too bad about the missed SD concert in T.O. If you'd made it here, you would have seen that my home built 5 shelf rack is almost identical to what you built. I used 3/4 MDF, rounded the corners, stained and with veneer on the edges. The shelves are 24 X 16 and have 20 inches of space between the threaded rods. If I want it even heavier, I now know to look at butcher block from IKEA. As one person had suggested for you to try, I covered the rods with brushed aluminum tubes with the same inside diameter as the threaded rod. I thought it would look a bit too industrial with the threads showing, and when I was buying the 4 - 36 inch rods, I noticed the aluminum tube in the same area and tried it for fit. Bingo! Perfect. The nuts are screwed tightly against the rod to prevent any rattling. Each of the 4 rods has a threaded spike on the bottom, to enable levelling. All materials except the threaded spikes, and MDF, from Home Depot. Annoys the hell out of the wife that it might chew up the carpet, but it has only been moved once, in a recent makeover of the room, and repainting of the wall it sits next to.