Ferret, sorry, this is not really an answer to your question. I have not used a plasma before, but my class on Manufacturing Technology (and a few other related classes) say that the edges of item might become case hardened. Also, if the pattern has some acute corners there is stress build up and a possibility of fracturing if the item is not cooled down properly (slowly), or warping.
I thought, while you're on the subject of using "exotic" cutting methods, have you thought of water jet cutters? No heat.