Here are some first round full scale sketch models. The focus here is to build them strong enough to hold the cables as well so in some cases the models are made of foam core but others are made of MDF.
The keyboard tray should retract away and not drop down so low that the user’s knee would hit it.
The keyboard try would hold a full size keyboard. Here it is modeled for a Mac slim size keyboard but inserts would be made to make it compatible with other keyboards.
Here’s the cable tray. It is built large enough to hold a power strip. Unfortunately I don’t have any dummy cables, power adapters or power strips to mock it up right now.