I don't know about Mapleshade but I purchased some 1.75" thick maple butcher block counter top pieces from Grizzley and cut it up to fit my components. Seems to work just fine. To be fair though, I have not done A/B tests with other materials or with Mapleshade products. Seems like it would be a lot of effort for what would be minor, if any, noticeable results.
what is the theory behind maple stands and racks?
I have not "heard" a maple amp stand or rack - using Billy Bags products now, which are made from steel and mdf - but don't grasp why maple would be a good material to use - quite the opposite. Maple is used for some electric guitars because it "rings" - it is very dense and causes notes to sustain, which is to say, it continues to vibrate for a long time. This would seem to be exactly the opposite of what one wants in a stand or a rack. If there is some claim that vibration is "drained away", well, if the rack is continuing to ring, that would likely cause acoustical feedback - the equipment isn't isolated from the thing it is sitting on. Can anyone who is not a vendor of these things explain the why of it, or relate positive experiences that seem to have a basis in fact?