I used one of my Buck 119 hunting knives on my first bow, worked pretty good as a scraper. I would probably use my K-Bar for roughing out a blank, or get my friend to let me do it on his bandsaw. I agree with Sleek, a drop point would likely be a better choice. Personally, I don't think spalted wood will hold up as scales, the spalted maple I worked with seemed to have lost at least 50-60% of it's weight, and likely some of it's strength. However, I like denser wood for scales, or antler.
Hawkdancer