You could also try used sail boat equipment
dealers, there is a boom on Latatude 38 right now, but at 17.5 feet too long. Rigging
shops some times have used booms and masts kicking around. Boat movers with storage
yards also get this kind if thing off of boats that are abandoned in their yards. Hope this gives you some ideas. I bought mine from a classified add on Latitude 38, 12 years ago. not sure where you are located, but I know of several places in California
where you could call and inquire.