Sha-banjo!

After seeing how the veneer joined on the outside, I was pretty sure I couldn't make it good enough on the inside with one piece, so I left the ends roughly trimmed and unglued and then came back to clean it up. After considerable hand wringing about making it fancy like they do with guitar binding and purfling, sensibility (my wife) won and I went with a simple maple wedge.

Making the channel straight was A PAIN (next time I'll try to trim the ends perfectly before gluing the whole piece), but making the wedge itself was fun. Just a little work on the belt sander and mainly running it over an upside down block plane a bunch of times and constantly checking the fit. It came out decent. Not perfect, but better than the outside butt joint.