Do people just not mess with them? It seems like most are metal or fiberglass. I have been playing with treating and tying bamboo for fun but it seems like there could be some potential there. Also, fiberglass backed hardwoods seem light and efficient but I don't know the what the upper limits are on poundage. I imagine that it takes a much longer wood prod to match the draw weights of the short metal ones.
I suppose it's all down to what type of bow you are after but I would be interested to hear thoughts about this from people who have thought a lot more about it than I have.