It would be undoubtfully useful to have a mode for canvas props that would display set cubemap as skybox when looking at that prop (sort of like those walls rendering through the map to skybox in Source). It could probably be implemented by making shader/material that only displays set cubemap
that way we can just surround any area with walls and enable cubemap mode on them so that surroundings would look like a real skybox and have drastically improved condo areas experience
This would be a great feature to add along with an artifical sunlight item
Also what software did you use to demonstrate the skybox cube? I thought it looked like hammer but the env_sun icon is different