I've never understood why a quarterstaff couldn't be made out of metal, or at least given a metal sheathe or metal ends. I hear they've even been made out of stone.

Likewise, you could probably replace the iron/steel in a weapon with hardened wood and/or stone. Admittedly, the druids with a wooden greatsword would look awfully silly, and all the fighters with Improved Sunder would look at him with a wicked gleam in their eyes.