I know you can do this in glulx, since I saw it done for exits in Aotoeroa.
Glulx Status Window Control seems to be the extension to go to for this, but I can’t get just a single word into a colour.
I have [wacky lights] as part of the status bar. I tried this:
To say wacky lights:
set the text colour of status window to g-pure-green;
reconstruct the status window;
set the text colour of status window to g-white;
reconstruct the status window.
But the ‘reconstruct the status window’ lines blitz the status window with a flash of green, and when it comes back, it seems to have shrunk to 1 line and become blank.