You might be able do your own. Golf dash clocks are illuminated from the front as apposed to a lot of cars that are back lit. I saw a guy's car that had taken the original clocks out and taken them to a photocopy shop and got the colours inverted, thus white dials.
Or you could try Venom as they do custom coloured dails and so should do 120mph clocks
Cheers
Biz