You may find this recent series of devblog's by Casey Muratori interesting. He goes into detail about his grass planting system. Less about the rendering side of things and more about proper placement of the ground cover itself to get the best coverage with the least amount of geometry. I don't think he goes into anything about LOD.. but it does get you thinking about how to provide the best coverage.
Starts in "Working On The Witness, Part 5" and continues on through his reasoning into part 8 where he has some code for optimal placement.