I did some search on LCD screens.
As it seems, the LCD screens use a polarising filter to be visible at all. Without the filter, the readings are simply invisible.
So, the orientation of the polarising filter defines if the display is a negative one (white readings on black background) or positive. Rotating the filter by 90deg, you change from possitive to negative and vice versa.
Obviously the positive display is by far much easier to read, contrary to the negative one. My understanding from reading in the net is that the only reason for going with negative display is that it looks cool!!!
Now, this filter is a film actually that it is glued on top of the LCD module. It can be removed and substituted by another filter with the proper orientation so that the diplay will be positive.
It sounds easier than it is though. Removing the OEM film is not that easy at all, it needs some surgical skills not to scratch the surface of the panel, and it requires quite some laborious cleaning of the display after to remove the glue residues. And finally, it needs some skill to apply the new filter without allowing air bubbles or dust particles.
I have found in the youtube some videos of people doing the mod on watches and other lcd displays. Polarising filters can be purchased even through ebay, and theoretically one can even choose different colors for their displays.
So the question is who will volunteer to treat his instrument cluster as a guinea pig ....