The notion of NVG compatibility is essentially just a matter of providing an illuminant that is sufficiently controllable at low levels so as to avoid creating excess contrast with ambient lighting. Toward that end, an old-school backlight based on incandescent lamps may be useful. See these for example. The physics of incandescent lamps is such that one gets significant shifts in both intensity and output spectrum as a function of drive level, which may be useful. Alternatively, an LED-based backlight might also be usable if provisions are made to operate it at abnormally low drive levels.
Additionally, an illumination scheme providing a positive switch legend (one where light shows through the legend, rather than around it) is also likely to be helpful, insofar as this vastly reduces the amount of unwanted stray lighting introduced into the environment. These are less common since they’re more bothersome to produce, but are likely to be found quite preferable.