I got a few good ideas on borders when I posted about this quilt last week. What I neglected to mention is that I would have preferred no border at all (as someone suggested), but I want to donate this to Victoria's Quilts so it required a 2-3" border on all sides to meet the size requirements.
That also meant that a double border (narrow inner border and wider outer border) wasn't an option either. I decided to go with this - a pieced border that tries to continue the basic shading design out to the edges. I think it works, and now at 51"x69", I can donate this once I get it into my quilting queue.