I'm unsure what the value of a laser finder on the ground would provide. I already know how high from launch point I am, and how far away through the telemetry data. Can you explain why you'd be interested in this?
If it was small and light enough to put on a drone to point straight down, that might be handy to have the data sent to ground via telemetry data in the app. I do see a day when DJI will find a way to do this, or some other way using Google elevation data, GPS, and launch elevation to calculate a reasonably accurate AGL altitude.