I would probably make some sort of smallish drunkard's path block of color set on point and alternating so you get a scallop/point sort of pattern... hope that makes sense.
So you would have the center and a band of solid, the band of curvy/points, and then another solid band top and bottom. You can double the width on the lengths (or halve them on the sides if you wish to think that way).
Now, I'm not much on planning my quilting and my quilting is more functional than artistic, but I would think having wide solid edges as a place to do something fancy could work well -- it's just that my brain doesn't think that way.