Liking the ideas. You could try rubber sheet for the desk surface. May be sensible to try a couple of samples first. Incidentally, I went for blackboard vinyl on mine - came out very nicely. Maybe worth a try. Fwiw, here's a pic of my customised desk which has been skinned with it:
For cable management, or concealing the cables, a vanity board would help with this. I've managed to conceal and organize my cables that way.
Will be trying plastidip myself at some point.
Looking forward to seeing this develop.
Edit: you could also use neutrik USB adapters to keep things tidy.