This looks fantastic, and it's just the kind of thing I was trying to imagine in my head. I wasn't sure whether it would be possible to have everything connected to the sit-stand desk, so that everything goes up and down together, but it looks like you have achieved that? Are your two secondary computer monitors on arms which are connected to the sit-stand desk? I would love to put together something like this - may I ask for some specs for what you have here? The frame, desk top, any other hardware (how did you put together the drawer system for the keyboard?).I just build a new adjustable desk, and have managed to place my master keyboard on a kind of drawer system. Really nice to be able to switch between sitting and standing. My master keyboard is a Yamaha S90es, a bit to the heavy side, but it works very well.
Take a look: https://www.dropbox.com/s/ljen6p1w9h4g6cf/IMG_0131.TRIM.MOV?dl=0
Many thanks @stigc56