yes! some people have made them.
material used is generally cast iron (meehanite) and they're cut from bar stock
there are several ways how to go about it. you could bore the bar to something slightly smaller than the final ID, then part it off.
cut the ring open , setting the gap.
hold the ring closed and lap the inside to final ID.
then, make a mandrel to hold it closed from side contact so you can hone the OD to final size.
then hone the sides to final ring height.