My first thought was this pattern:
http://www.bellaspatchwork.com.au/it...lt-Pattern.htm, Baby Mine the "girl" version. But then someone mentioned Nine Patch Pizzazz:
http://www.amazon.com/9-Patch-Pizzaz.../dp/1571203230. I think that would be even better! I do think you should add some darker values, as others have already said. Be sure to show us your finished project!