That looks really nice! I think you have inspired me to making some boards for my PA and inlaying them as well.
The biggest MOP plates you will get are only about 1.5 inches a side, so a pattern will have to be pieced together for a fish of any size, but it can be done fairly easily with a little work. There is also the option of Ablam sheets that are much larger. Here is my small bore silhouette levergun I did a while ago, now I'm anxious to start cutting pearl again!...
