Haven't run across any such cases yet. (Doesn't mean they haven't happened; just means I haven't run across 'em.) The gun-mounted light is still fairly uncommon in CCW, though we'll see more of it as the lights get smaller and the concealed carry holsters catch up with that design concept, both of which are already happening.
Two informed predictions, though...
First, expect a lawyer who has to manufacture a case to come up with the same BS we saw with night sights and laser sights already: "Ninja assassin of the night, blah-blah..." My prediction: a good lawyer and a gun-competent defendant will employ expert testimony and/or material witness testimony from defendant's trainers to destroy that false assertion and show that paying extra in both money and inconvenience allowed the shooter to have equpment that guaranteed he wouldn't mis-identify a threat in the dark and shoot the wrong person. In short, the defense ends up showing the defendant was highly cautious and responsible, and far from negligent or malicious.
Second, expect a test case in which someone used the gun mounted flashlight as an illumination tool instead of a lethal weapon and "muzzled" someone at whom he had no right to point a loaded gun. (Felony aggravated assault charge, and all of that.) Do like the cops: when you carry a gun with a mounted flashlight, reserve it for high danger situations and ALSO CARRY A REGULAR, SEPARATE FLASHLIGHT for routine search, identification, etc.
We'll see what happens when the first test case rears its head. In the meantime, if you use it cautiously and reasonably, I certainly wouldn't see a problem with it.