Doc,
Designing scroll work for those small brass areas is going to be difficult. The scroll will be so small that your work will have little visual impact unless you hand it to someone and they look at it with a magnifying glass. For a few years I carried a 14 inch Bowie with stag grips made by A.G. Russell. It had plenty of brass to engrave and when I was done with it it looked great but it was too big. I looked all over the internet and with custom builders and couldn't find what I wanted. Finally, while I was in Branson, MO for the MO state shoot I found a smaller Bowie with plenty of brass to engrave. This thing will never win an award at the Blade show but it cost all of $27.00! Below is a picture. I just went down in the shop and shot it with my pocket camera but you will get the idea what it looks like. The sheath was made by Wayne Craig who does all of my cowboy leather. The sheath cost as much as the knife.
ROger