Total Commander

It would be great to associate each drive with a unique colour, and display this colour as the background of the file-list panel.

Total Commander makes it almost too easy to perform operations on the wrong drive. This visual aid would enable "LIVE" drives to be colour-coded red, for instance, and definitely make you think twice before deleting or overwriting on such a drive.

Why don't you simply colour the files which are on a specific drive?
This can easily be done under >configuration >colour >Define colours by filetype.

Use the internal tc.plugin for that, something like "path contains X:\bla".

You can also use NTFS rights to protect files from overwriting or deleting.

Icfu

Yes, this is definitely an option, but I would still want to be able to colour-code by filetype as well.

I merely used the delete/overwrite functions as examples, but the usefulness stretches much further and it would be nice to, at a glance, immediately know what drive you are working on.