Making that huge cube thing black instead of white will tend to visually subdue it, but it will still be there... hopefully not so noticeable from the street.
I'm all for some kind of light feature - instead of trying to hide it, maybe it might be better to dress it up a little. Maybe put one of those huge 1980s vibe digital clocks on it like the Skye project - make huge retro digital clocks a Halifax trademark! We can make them cool again!