you're probably going to have a hard time finding grips that are both as thin as you want and wood. There's only so thin you can go with wood before it becomes really flimsy. Plastics or metal can be made a lot thinner while remaining durable.
You could try finding a cheap set of wood grips and sanding them down, but just be aware the thinner you go the more likely the are to split when you use them.
si vis pacem para bellum