I made a couple of these for my hangar.
Instead of the standard two foot bench, I ripped a sheet of 3/4 into three foot and one foot.
Still have two feet of work space, with cubbies I find useful.
The one foot rip becomes the top shelf
My other work benches use solid core doors I found at Habitat for Humanity's Re-Store.
They have wheels so they can be reconfigured easily for various airplane projects.