Seems like this request hasn't gotten much traction, but I'd like to show my support for it. In addition to D&D I'm running a Lancer campaign, so having the option to define a custom map measurement unit (Light-years, Parsecs, etc.) would be extremely helpful.

The best I can do at the moment is use either Miles or Kilometers, but both of those result in absurdly large numbers when used accurately so it ends up being rather unhelpful. My current workaround is to just use Miles, but make a note that each Mile on the map is instead a Light-year.