There's not all that many out of a couple hundred bows that I have made without using my trusty scoop-like Surform rasp, the one used in one hand in a pulling motion. It eats even the hardest woods, never taking off too much, following stave contours, managing dips and handles. Importantly, it allows me to make bows free-form, without a vice, horse or anything other than my hands and toes (yeah) to hold the wood and work on it at the same time, fluidly.
Costs around 10 bucks, indestructible, with cheap replacement blades (you need to change once in a while to keep up the performance), light and small enough to take with me anywhere. Along with an axe and a cabinet scraper all I need to cut, rough out, tiller and finish a bow.
Tuukka