You might ask your brother-in-law about his daughter's favorite colors to start with. If this individual gives you incomplete answers, ask the gal's mother. But above all I would suggest something that you would like.
I have been reading some of the comments from others and I like the idea of just simply asking the bride for what color grabs her heart. Then you can dive in with any pattern old, new, modern or traditional that brings you pleasure in creating with that color and coordinates.
I personally like the quilt from himnherr. It is a traditional pattern but being off set makes it modern and it is easy to make. Take her favorite color and run for your stash!