where can I find big artsy wooden buttons?

Do you have any arts and crafts stores near you? That might be a good place to start looking.

Britex Fabrics downtown near Union Square. Mendalls on Haight Street.

You can find ornamental buttons in just about any sewing shop. Even chains such as Joanne Fabrics carry ornamental buttons. BUT I know that some people make their own ornamental buttons out of Fimo. Of course these are not as sturdy as bone buttons but they are as solid as alot of the plastic buttons. I’ve had friends use wood discs and then cover them with fimo or paint the discs and then seal them. You can also learn to make your own forms and mold your own plastic creations.