You could do a pattern like a trip around the world but adjust the color. You might go on Robert Kaufman website and start looking at all the colors they have.
http://www.robertkaufman.com/fabrics/kona_cotton/
Ombre fabric is probably only 42" wide with the color graduation. Take whoever came up with this idea shopping for fabric. It seems they have a specific idea in mine. There is a post on QB from a woman looking for a beach quilt since her son is going to married in Redondo Beach.
http://www.quiltingboard.com/main-f1...t-t260127.html
I posted a reply about a quilt called Surf Song. It may be a Bargello but other on this board will tell you it is not difficult. You may want to search this pattern on Google and see if they would like the various color combinations.