Wedding ring in colors of their choice would be good. Flynnquilt.com
http://flynnquilt.com/ has templates for a large block size, and instruction books for an easy way to make them.
The medallion quilts are always a good choice. An Amish style quilt (square block in center with border around it then filling out the rest of the quilt with solid colors) would be fairly easy to do.
You can see lots of quilt blocks at quilterscache.com
And asking them is always good.