I previously owned a Leica Locator Plus which is the civilian labeled version of the Vector IV. It was rated for 4,000 yards and would do that easily in bright sunlight. It was an absolutely wonderful unit. I sold it several years ago because it was bulky and heavy...plus I found I never really used its full capability. I assumed I would easily find a lower range, lighter unit but I have failed so far. Reticule color is one serious limitation for me. I can't see the red/orange color of the Swarovski or Leica units you guys use.
In any case, my real point to make here is that even the 4,000 yard, million dollar Leica/Vector would not consistently range a deer at anywhere near 1k on a flat field, nor a smaller coyote past several hundred yards. Even with the Locator Plus I finally conceded that there just simply is a limitation on what the best units will do.
Trying to find the holy grail of range finders is a little bit like chasing your tail. But it is fun to do!