The idea was to create a couple different "platforms" that could be easily swapped out depending on what the priority was. When I am messing with my synths, I like to roll the stand over and use 6 foot cables to patch into the patch bay so that I can run the signals from the the synths to the pedals to create unique and groovy sounds. I have also decided to add "feet" to the pedal board so that it can also be used on the floor when playing guitar. When the pedal board isn't being used in those capacities, it lifts right off the stand and sits on top of one of my racks of gear where it's close enough to the patch bay that I can use it for mixing to patch in effects.
I did all of this impromptu, so sorry if you were hoping for detailed plans, but it's a pretty simple task if you have a couple power tools. I bought a couple of pre-cut 2'X2' squares of plywood from Lowe's and I had felt fabric left over from my DIY bass trap project. I used 3M spray adhesive and also a staple gun to reinforce the felt's placement. The felt came from JoAnn's Fabric but there are cheaper sources, especially if you live in a big city. I basically laid the plywood sheet on top of the mixer stand and traced where the arms were touching it so I knew where to cut the slots so that the arms could slide through. Then I took a drill to cut a couple holes on those slots and did the actual cutting with a jigsaw so that the slots were about 1/6" wide which makes for a nice snug fit onto the stand and keeps the platform from falling off. I trimmed about 6 inches off the top to prevent it from being too heavy on that edge and mounted a power strip underneath. For the guitar pedal platform, I used this single awesome 9V power supply to daisy chain one cord to most of the units. The Q-Tron takes 24 volts and the Moog pedals are finicky about the connector.
Pretty basic design but it was just what I needed for this room. Very sturdy. Very practical and versatile. That's a win for me.