Man, you must be diggin some tuff stuff. I'd think structurally, fiber glass or carbon fiber might hold up but they won't hold up to the abrasion. As was mentioned, just get a Lesche or a shorty Sampson, 18" or 31". The only time I saw a Sampson bend was when a guy tried to pry, out of the ground, a 5" diameter tree root by standing on the handle. Then it only bent a little and was easy to straighten. I don't mean it bent right back in my hands but jammed into a crack in two big rocks, then we both pushed it. Eventually it got straight. They're tuff enough tools.
