This is going to sound ridiculous but I swear this was available on the 5D3. I've searched the manual for "screen color" and "lcd color" and there's nothing. I could've sworn I've changed it before and my 550D has it, it might be a option available on lower end cameras for customization since honestly I don't think anything more than black on white and white on black is necessary but who knows.
If you don't know what I'm talking about it's the option to change the color scheme of the LCD between: black on white, white on black, yellow on black? and pink.