I would make two curved templates (one for long side of the frame and one for the short side). I would make the templates a couple of inches too long (no miters), and mark the centerline on each template. You can then use those templates to make the center, then make the four sides (cut inside curve on each side first, then miter it around the center using the outside of each side as reference for the miter, then cut the outside curve on each side) Once all of the pieces are a tight fit together with butt joints, I would use splines to hold it all together
Sounds like the pulls have it. I'm thinking something in wenge to match the solid wood edge banding, with the quarter sawn side out so the grain isn't too distracting. It's too bad Eric doesn't take commissions...I really like the pulls he made for his "pair o' nightstands."