Captain’s Log, Stardate 95825.73: I am extremely happy with this setup.
Those wooden clamps are custom made (and a bit Frankenstein-y; the prototype became the final product as I tweaked it). Each one is just two strips of construction lumber, about 7/8" thick. The jaws are brought together by two bolts which screw through t-nuts on the bottom strips. Tighten down with a ratchet.
From there, I’ve embedded several t-nuts into various locations on the bottom strip which fit the camera mounts (adding more as I found the best location for the old, inferior mounts).
The trackpad is a Magic Pad. I attached a scrap piece of plywood with an embedded t-nut underneath it; the plywood is attached to the trackpad with removable but strong 3M Command Strips.
These are absolutely wonderful mounts; the ones I used before were garbage; these have much greater range of motion and are stabler and easier to adjust. I have 3, one for each keyboard half, and one for the trackpad:
The least stable components of the setup are the chair arms themselves, which is not bad at all. The chair itself is a Steelcase Leap. The arms of the chair are pretty adjustable and integral to getting the tools where I want them.
The USB cable for the keyboard presented a bit of a challenge. Currently I’ve used an extension, and the cable is run behind the chair and up the back, through a wire hook hanging from the ceiling. From there the cable runs to my USB hub at the back of the desk. This works fairly well, but a longer cable would be better. There is one on the way (along with a Lightning cable for the trackpad so I don’t have to worry about charging it, which will run the same way), and that will complete my rig, I think!