Out friends at Black Sheep Warrior are working with Mesa Manufacturing to produce the new Megiddo M-LOK Rail Covers. These M-LOK compatible rail covers are machined from G10 and will available in a variety of lengths and colors. G10 is a good choice for this application because is lightweight, has the ability to take aggressive texture, and is impervious to most solvents.
They are planning on releasing the Megiddo in 1, 2, 3 and 4 slot configurations and Black, OD Green and Brown color options. Check out Black Sheep Warrior for more details.