I think there's a market for it, but it won't beat a path to your door - you have to advertise that you do it, and reach beyond your local area. Most people when they think hand quilting, think about the Amish. They have websites offering their services. You might google Amish hand quilting and see what they charge.
You can probably get work, but I don't know if you can make a living doing it. And by the way, 8-10 inches is just fine.
Janet