Ross has you covered. Corning comes from the salt curing process. The chunks of salt used in the curing process being corn like some would say, but much of that is lost in history.
I have been planning on corning a silverside roast, as I have read that the Aussies prefer that for their corned beef. While a bit more expensive, there would be less waste and the end product would be much leaner. Once corned, all that is needed would be a pastrami rub and some smoke.
The purists will tell you that it must come from "navel" meat. The brisket as we know it is more common for American corned beef. Actually, all sorts of meat like turkey are now being sold as pastrami, referring to the process more than to the original dish made famous in the old New York Jewish deli's.
Good luck and good smoking.