I'm linking up at WIPs be Gone, and A Quilted Passion today.
Thanks to a comment below, I had another inspiration. The reason I wasn't considering Bonnie's plan (which would be purple/black in my colour scheme) is that my purple and black are too close in value. But, what if I slip a little bit of brown in there between them? So a 1" purple, 1/2" brown, 5" black border.