would be nice to have a different background colour

[mattvenn]

could this default to black but override in the tech file?

[trilomix]

Hello MattVenn,
Everything is possible.
Do you mean change the background black background color in the 3D View?
If this is your purpose, then I think the best is to add an option in the command line. As the tech file is technology dependent and we can introduce conflict if more than one tech file is used.
I already change the background color while taking a snapshot that allow to have a transparent background the snapshot is used for something else.

Regards,

Trilo