A replica Colt Walker Dragoon? Sure. Use a template and use regular wood stain with a wee paint brush for the colour. Wood burning would look kind of slick and shouldn't need any colouring too. Just remember to put on a wood sealer.
Be very careful with a rotary tool though. Get her some scrap hardwood to practice on.
Gonna make your own holster? Think Tandy's. They have pattern and how-to books.
