It's never too early to start checking out button possibilities for a project. From my button collection, here are three prospects for Isabel's vest (she rejected out of hand the idea of pewter clasps).
The ram's head and the painted wooden buttons are from Philosopher's Wool. I'm not sure where I picked up the other. Isabel is voting for the celtic swirl, I'm voting for the wooden one, and so far no one is picking the ram's head. Is it too masculine?