Ok so how viable are crosses between different locales? I would say very. I have read a lot of comments about keeping the gene pool pure to maintain the uniqueness of a specific locale. This may be a valid way to keep what nature is currently displaying but it is also the same nonsense logic that give us dog "breeds". That being said I am not advocating that we should cross willy nilly, but if you want to preserve and enrich the captive gene pool than some crossing will be needed and only with those species that are likely to encounter each other without human help. The notion of pure blood lines is a load of nonsense mostly because it leads to health concerns and (an important part of this) People are selectively breeding animals. Meaning they are breeding to intensify the one color. Since this is happening the idea of cross breeding is required to maintain the "breeds" long term health.
That was the genetics side of the argument, the evolution side of the story is a bit more intense. More than likely what we are actually discussing with locales is the early divergence and local adaptations. This is based on our knowledge of when Madagascar separated from Africa at a relatively late in time. Given I have not research the phylogeny of chameleons, I would safely assume that the nearest relatives of the panthers would be the small islands and then a species in Africa. It is also likely that female choice is driving the differences in the locales color since only males really show vivid colors.
